问题补充：
— If you have any trouble, be sure to call me.— .
A. I am glad to hear that.
B. I will. Thank you very much.
C. I have no trouble.
D. I will think it over
答案：
A. I am glad to hear that.
(答案→)B. I will. Thank you very much.
C. I have no trouble.
D. I will think it over
解析：题干的意思是“如果你有任何困难，一定要给我打电话。”，根据英语的表达习惯，当别人帮助我们或夸奖我们时，我们应该表示感谢。所以只有B选项是正确的。其他选项不符合英语的表达习惯。所以本题选B。
