Whilst all the answers given here are correct in some way, the correct one is still A, preventing a war in Vietnam. The 60s were a hippy era, the pacifist movement against wars. And since the war in Vietnam lasted for 20 years, it is obvious that that is the thing which colored their lives black and something they stood against the most.
Answer:
A comic strip from the lesson? I can re-edit my answer when you reply if you want.
Explanation:
