The correct answer is A. The Vietnam War.
The 26th amendment is the law that allows 18 year old American citizens to vote in elections. This was passed in 1971.
The Vietnam War resulted in thousands of 18 year old males serving in the military through the draft. Many of these citizens felt it was unfair that they could be drafted into war but could not pick the representatives who agreed to send the US into this war. This is why many 18 year old military and normal citizens protested for an amendment that allows 18 year old the right to vote.
