How have attitudes toward cleaning up Vietnam changed over time ?

As reports from the field became increasingly accessible to citizens, public opinion began to turn against U.S. involvement, though many Americans continued to support it. Others felt betrayed by their government for not being truthful about the war. This led to an increase in public pressure to end the war.

Explanation:

wait history, who want to talk about history, boring.

the answer is d. selective incorporation. (apex)