the doctor told him to get more exercises ( ) his health.应该选哪个,为什么?

题目

the doctor told him to get more exercises ( ) his health.应该选哪个,为什么?
A.for the reason of B.for the case of C,for the sake of D.for the cause of

答案

for the cause of 没有这个短语,难翻译成为了健康的原因吗,cause已经是原因的意思,而for 本身有为了的涵义,所以无此固定短语.for the sake of 为了.起见 固定短语