In 1965, as the conflict in Vietnam intensified, the United States
declared war against North Vietnam.
decreased the number of US troops in Vietnam.
O escalated its troop commitment to the conflict.
O began defending North Vietnam against the Viet Cong.

The Vietnam War and active U.S. involvement in the war began in 1954, and

Nixon had gradually reduced the number of U.S. troops in Vietnam in several stages.

I believe it is the first answer.

Explanation:

Escalated its troop commitment to the conflict

Explanation: In March 1965, Johnson authorized the dispatch of U.S. battle forces into fight in Vietnam. By June, 82,000 battle troops were positioned in Vietnam, and military leaders were about 175,000 more before the end of 1965.

b.provides a written record of the transaction

ok

explanation: