How does this sentence contribute to the effectiveness of Du Bois' argument overall?
(A) -It underscores the limited success of Washington's program and implies that it could have done even more harm.
(B) -These movements are not, to be sure, direct results of Mr. Washington's teachings; but his propaganda has, without a shadow of doubt, helped their speedier accomplishment.
(C)- It emphasizes Washington's influence and effective leadership while questioning the motives behind his program.
(D)-It acknowledges that other factors have contributed to the situation and reveals his negative view of the ideas Washington has promoted. It downplays the validity of the information Washington has provided while outlining its negative effects.​