Question

Why did U.S. public protests against the Vietnam conflict escalate over time?

A. People were growing less confident in a chance for American success.
B. Returning soldiers were speaking out in large numbers against the war.
C. Military leaders acted in ways to continue the war for their own gains.
D. Thousands of war refugees were migrating to and flooding American cities.

Answer 1

There are multiple reasons people didn't want to go to Vietnam.  Firstly, it was immoral and people didn't like the fact we were going to a third world country and massacring it's people.  Many also thought that the whole mission lacked a clear objective and appeared unwinnable.

TL;DR - It's probably answer choice A