— I think students should have mobile phones to call their parents.—. They often use them

问题补充：

— I think students should have mobile phones to call their parents.

—. They often use them to play games instead.

A. I hope so

B. I don agree

C. No problem

D. Good idea

答案：

A. I hope so

(答案→)B. I don agree

C. No problem

D. Good idea

解析：I hope so希望如此；I don agree我不同意你；No problem没问题；Good idea好主意。句意：为了给他们的父母打电话，我认为学生们应该有手机。根据下文，他们反而经常用它们来玩游戏。可知前文为否定回应。故选B。