Option: A. He sent more military equipment, more money, and thousands of advisers.
Explanation:
After the exchange of letters with South Vietnamese President Ngo Dinh Diem, President John F. Kennedy decided to take action against the communist insurgency campaign in South Vietnam that was spreading and feared that it will result in the domino effect after Vietnam. The military support involved intensive training of local self-defense troops by American military advisers. There were more than 16,000 U.S. advisers in South Vietnam in Kennedy presidency.
