Tom is not ______ he was in the situation ______ he was pessimistic.
A.where; whenB.what; whereC.that; in whichD.what; that在线课程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。