下图中活动C的自由时差是（）。 

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SQL Error: select id,body,options from ***_enewstiku where sourceid='27072' and id < 2244096 and id<>'2244096' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='27072' and id > 2244096 and id<>'2244096' order by id asc limit 5