Answer:
B) The Bolsheviks.
Explanation:
The Bolshevik Party, headed by Vladimir Lenin, was a radical Marxist party. They took advantage of the chaos, instability and famine brought about by the participation of Russia in the First World War. Lenin was in exile, but he was sent by the Germans in a train from Finland to Russia to cause more chaos and agitation. Lenin had his own agenda, nevertheless. The Czarist government fell in February 1917, and the temporary democratic government that succeeded it fell in November as a result of a revolt by the Bolsheviks that put them in power.