问题

How did your mathematicsexam go—I thought I ,but in fact I fell behind in the class.
A:should have been the top 10
B:could have been the top 10
C:may have been the top 10
D:need havebeen the top 10
B:could have been the top 10
C:may have been the top 10
D:need havebeen the top 10
正确答案是: