The new lecture course differs from the old one, the students aren't required to attend lectures.
A. which that
B. that
C. which
D. in which
网友回答
A. which that
B. that
C. which
(答案→)D. in which
解析：根据句意可知，逗号后为定语从句，先行词为the old one，由于定语从句不缺少主要成分，当先行词还原时只能作状语，此时只能选择“介词+which”或“where”作连接词，由此可知答案为D