the U.S. play the role as big brother by bringing troops, guns, and supplies into Vietnam. they werent successful because they thought it would be like korea but instead it was a very mountainous terrain and heavily vegetated. also, the vc and north vietnamese army were a guerilla army which the us was not prepared for.
I know that this isn't what you're looking for, but the answer is not B. The rebellion brought about a decline in race-based slavery. I know because I took the quiz.