The answer is on the first part; Opening of the Interview. The first part in doing an interview is crucial because this is where you'll establish rapport by giving the purpose of the interview and outlining what the interview is all about. Giving the purpose of the interview also allows to interviewee to be prepared in the next parts of the interview.
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.