He did his homework carefully for fear that he would make a

He did his homework carefully for fear that he would make a mistake.这是我的书上的答案但是在另一个百度知道的问题中,答案确是He did his homework carefully for fear that he ( ).A.made a mistake B.makes a mistake C.would make a mistake D.make a mistake 选B,因为前面是有for fear 所以后面要接一般现在时态哪个对?我这个书上的.