The correct answer is letter D. The sacrifice involved with choosing one over the other. When deciding between two alternatives, they should consider that.
I believe the answer is: It lowered the voting age to 18.
The 26th amendment was created in 1971. Prior to this year, the majority of the 18 years old are either already working in some ways or being drafted to join a war. Since they have to carry a lot of burden, it is only fair if they also could give their vote to appoint the government officials that can represent them.
The answer is going to be D