The Berlin Wall Was Constructed in the Fall of 1961

The Berlin Wall was constructed in the fall of 1961 by the

A) U.S.to protect American,French,and British troops stationed there.
B) U.S.on the grounds that East Berliners were fleeing to the West and must be contained.
C) Soviets on the grounds that the Western presence threatened their security.
D) Soviets to stem the tide of West Berliners from pouring into East Berlin.