[求助]GWD-TN-21-37

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 .

                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

答案是E,但我看好像都不对