His friends are not happy with him because he always turns down

His friends are not happy with him because he always turns down their invitations ______ ill health.
A、on the grounds of
B、on the strength of
C、in view of
D、by means of
【正确答案】：A
【题目解析】：译文：他的朋友们和他在一起很不开心，因为他总是以不舒服为由拒绝他们的邀请。固定搭配on the grounds of表示因为，on the strength of凭借（或根据）某事物，在某事物的影响下，in view of sth.考虑到，鉴于，by means of用方式。答案为A。