咨询prep一道sc题，请高手解答一下

duoduotji

The Iroquois organized their kinship groupsinto matriarchal clans, of which members traced their descent from acommon female ancestor

A.       of which members

B.       with members who

C.       members of whom

D.       whose members

E.        of members who

答案选的d，请问为什么不选C呢？请高手帮帮忙解答一下

Augustus8

逗号后面的定语从句缺少主语（谁traced ）whom在定语从句一般充当宾语成分,所以要排除。D项whose指代matriarchal clans,是说这些个clans的成员，做从句主语