Answer: a) Dean Rusk
Explanation:
Dean Rusk was one of the longest serving Secretaries of State in the history of the position having served under both President Kennedy and President Johnson. Being the SOS to President Johnson, he was directly involved in most of the Vietnam War.
It is said that initially, Mr. Rusk did not want the United States to get too involved in the Vietnam war but he changed his stance as time went on and advocated for an escalation so that the U.S. could defend South Vietnam.
