下列药物中，可能导致血小板减少症（药源性血液系统疾病）的药物是（）

A.巯嘌呤

B.环磷酰胺

C.阿糖胞苷

D.甲氨蝶呤

E.利福平

-My cat's really fat.      

-You___________ have given her so much food.                                                              

A. wouldn't                      

B. couldn't    

C. shouldn't                      

D. mustn't