I would say C because it’s always best to get other’s opinion on how something can be fixed or even be worked on to be better.
I believe the answer is B.
The option that most effectively completes the sentence is “allowing world nations freedom of choice, within reason, promotes peace”. According to John Kennedy in his speech delivered at the American University, nations (in this case he refers to the Soviet Union) should not try to impose rules on other nations as this interferes with the process of peace and creates tension.
