Harry Potter is the most interesting book_____I have ever read.

Harry Potter is the most interesting book_____I have ever read.
A、that
B、when
C、who
D、where
【正确答案】：A
【题目解析】：本题考查定语从句。句意：《哈利•波特》是我读过的最有趣的书。先行词是book，从句中缺少宾语，引导词可用that或which。但先行词被形容词最高级修饰，引导词只能用that。故本题选A。