The boss refused to sell the car for ________ he thought was not

The boss refused to sell the car for ________ he thought was not satisfactory.
A、that
B、which
C、how
D、what
【正确答案】：D
【题目解析】：考查宾语从句的连接词。此处he thought为插入语，what作宾语从句的主语。句意：那位老板拒绝以不满意的价钱买车。