求NN解释一下！！！

pengfu

United States SenatorDaniel Inouye was appointed to several posts within the Democratic Party duringhis first term, that included assistant majority whip and vice-chair ofthe Democratic Senatorial Committee.
A.    that included
B.     which includes
C.    including
D.    some of which were
E.     among them being
为什么不能选择D?prep笔记中说是由于和posts隔得太远。。。。希望有大牛能详细解释一下，谢谢！