Question

Barron's 的sat题目，答案是B，解释是要改写成in which来引导noun clause。In which和where不是等同的吗？

In the aftermath(A) of the space shuttle Challenger explosion, where(B) seven crew members were killed(C), the NASA program underwent a massive examination(D) of priorities. No error(E)

Answer 1

where表示地点吧 怎么引导一个noun clause？
还有前一句的中心词不是aftermath吗？