Tom is not ______ he was in the situation ______ he was pessimistic.

A.where; when

B.what; where

C.that; in which

D.what; that

答案及解析： B

解析：

本题考查名词性从句及定语从句。what引导表语从句，在从句中作he was的表语；

先行词the situation在从句中作地点状语，选B。