Her sister has become a lawyer, ________ she wanted to be.

A.who

B.that

C.what

D.which

答案及解析： D

解析：

此题考查的是非限制性定语从句的用法。先行词为前面a lawyer。A项代指“人”，而此处指职业；

B项不能引导非限制性定语从句；

C项只能引导名词性从句，故D项最佳。