一道高中英语从句题（Theschoolsthemselvesadmit……）Theschoolsthemselvesadmitthatnotallchildrenwillbesuccessfulinthejobs___theyarebeingtrained.AinthatBforthatCinwhichDforwhichA,D都是“因为”,在用法

　　一道高中英语从句题（Theschoolsthemselvesadmit……）

　　Theschoolsthemselvesadmitthatnotallchildrenwillbesuccessfulinthejobs___theyarebeingtrained.

　　Ainthat

　　Bforthat

　　Cinwhich

　　Dforwhich

　　A,D都是“因为”,在用法上有什么区别?

　　C为什么不可以呢,“不会在他们被训练的工作中成功”