Smoking, _________ is a bad habit, is nevertheless, still popula

Smoking, _________ is a bad habit, is nevertheless, still popular.
A、though
B、it
C、that
D、which
【正确答案】:D
【题目解析】:考察非限制性定于从句,___is a bad habit 为从句部分,先行词为smoking,因此要用which来引导从句