Answer:
I believe B is the correct answer.
Explanation:
A is quite useful, but it's not necessary for our goal of world peace.
E is too vague and doesn't help the cause. How do you simply 'stop a war' and how can we ensure that more wars won't arise in the future?
D does stop a war from going on, but it doesn't solve the problem of wanting world peace, as more wars can arise in the future.
C, as the idea, is really cool, again, how will it help our cause of wanting world peace?
I understand that you can choose multiple answers here, but you can't simply change one's mind just for the sake of wanting peace. Wars are a problem and do take part in world peace, but that doesn't change the fact that someone is not at peace with others. You've got to change their minds, not just the idea of wanting to go to war.
Please, do tell me if I got this incorrect.