What caused Russia to exit World War I in 1917?
A. the death of the czar
B. a revolution within Russia
C. a surprise invasion by Poland
D. the bankruptcy of the Russian treasury
It was "B. a revolution within Russia" that caused Russia to exit World War I in 1917, since the communists removed the Czar from power. It should be noted that this eventually led to the Czar's execution.
