Which of the Following Best Describes the Military Situation on the Eastern

Which of the following best describes the military situation on the Eastern front?

A) While the Austrians were able to defeat the Serbians, Germany had to rescue them from a Russian attack.
B) The Eastern Front was also a stalemate beginning in the fall of 1914 and lasting until the Russians left the war in 1918.
C) The unexpected Russian attack in 1914 resulted in the Russian occupation of East Prussia until the Treaty of Brest Litovsk.
D) The war involved less stalemate, and German territory was inviolate after August 1914.
E) German successes were spectacular initially, but after three years of stalemate, the Bolsheviks were able to push the German back to their positions in August 1914.