Harry Potter is the most interesting book ______ I have ever rea

Harry Potter is the most interesting book ______ I have ever read.
A、which
B、where
C、when
D、that
【正确答案】：D
【题目解析】：译文：哈利?波特是我曾读过的最有趣的书。先行词的定语为形容词最高级时要用that引导定语从句。