What Led to Republican Control of Both Houses of Congress

What led to Republican control of both houses of Congress in 1946?

A) Large numbers of middle-class voters voted Republican, while workers stayed at home.
B) Martin Luther King led civil rights demonstrations, and Democrats were painted as a party for African-Americans.
C) Congress failed to pass the national health-care plan so Democrats lost support.
D) The additional New Deal programs were not extensive enough.
E) France lost control of its Vietnamese colony.