问题补充：
People today make choices of their diets what they believe.
A. based on
B. basing on
C. are based on
D. being based on
答案：
(答案→)A. based on
B. basing on
C. are based on
D. being based on
解析：考查短语：be based on 以什么为基础，在这里based on做后置定语，修饰their diets，相当于定语从句which are based on，故选A。
