甲、乙、丙、丁四个方案为互斥方案，其现金流量如下表所示，折现率取12%。若方案分析采用净年值法，则较优的方案是（　　）。方案初始投资(万元)计算期(万元)每年效益(万元)净年值(万元)<table style="BORDER-COLLAPSE: collapse" border="1" cellspacing="0" cellpadding="0"><tbody><tr><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">方案</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">初始投资（万元）</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">计算期（万元）</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">每年效益（万元）</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">净年值（万元）</td></tr><tr><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">甲</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">1000</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">6</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">200</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">-43.23</td></tr><tr><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">乙</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">1000</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">8</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">260</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">58.70</td></tr><tr><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">丙</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">2000</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">12</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">350</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114"></td></tr><tr><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">丁</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">2000</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.2pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">15</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114">300</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: rgb(255,255,255); PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 85.25pt; PADDING-RIGHT: 5.4pt; BORDER-TOP: rgb(255,255,255); BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm" valign="top" width="114"></td></tr></tbody></table>[注：(P/