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.

a, both were musicians during the jazz age

abraham lincoln  (february 12, 1809  – april 15, 1865) was an american statesman, politician, and lawyer who served as the 16th  president of the united states  from 1861 until  his assassination  in april 1865. lincoln led the nation through the  american civil war, its bloodiest war and its greatest moral, constitutional, and political crisis.[2][3]  he preserved the  union,  abolished slavery, strengthened the  federal government, and modernized  the u.s. economy.