一个神句。。。我怎么也看不懂意思，找不到主语。。。求解答。。。。

xly878

In 1994 the white house named Dr RuthR. Faden chairperson of the federal advisory committee of experts they assigned to do a report on the history and ethics of the government’s radiation experiments on humans in the 1950’s and 1960’s .
federal advisory committee of experts it assigned to do

A. they assigned to do
B. to be assigned doing
C. that was being assigned doing
D. ! assigned for doing
E. it assigned to do  

37题  GWD24套中第20套  正确答案是E

求解答。。。。句子啥意思，主句是啥。。。。

期期啦啦

name Dr.. chairperson...(whom) it saaigned to...

词组name sb sth ，it assigned 做定语从句，省略whom