When she was in trouble, I did what I could to help her.my help, she wrote me a letter of

When she was in trouble, I did what I could to help her. my help, she wrote me a letter of thanks.
A. In honor of
B. In case of
C. In terms of
D. In return for

A. In honor ofB. In case ofC. In terms of(答案→)D. In return for解析：考查介词短语：A. In honor of为了纪念B. In case of如果，万一，C. In terms of就…而言，D. In return for做为回报，句意：当她有困难的时候，我极尽所能帮助她，做为回报，她给我写了一封感谢信。选D。

这个解释是对的