Why did america first not become involved in the activities in europe? why did america later enter world war ii?

The correct option is the first one of the list. As part of the Geneva Accords that ended French colonial rule in Indochina, Vietnam was divided into two countries.

The Conference passed between April 26 and July 20, 1954 during the Indochina War between France and the Democratic Republic of Vietnam.

This conference was of vital importance for the French colonialist pretensions to continue dominating Vietnam within the French Union. For the same reason it was of great value to HoChi Minh, president of Vietnam, and his aspirations for full independence and sovereignty.

It was held after the French defeat in the battle of Dien Bien Phu and for this reason the position of France was very weak, because it could not present itself with a decisive victory over the Viet Minh, as was its initial objective, nor with the battle yet to decide.

In this conference it was approved, among other points, the partition of Vietnam in two states by the 17th parallel: North Vietnam with capital in Hanoi, and South Vietnam with capital in Saigon.