Answer:
The Russian Social Democratic Party became "The Communist Party" at the end of World War I, bringing down the empire of Tsar Nicholas II and led by Lenin and a revolutionary group called "The Bolsheviks", so "the Bolshevik Revolution" is the same as "The Russian Revolution" which developed into the comunist state known as:
"The Soviet Union", a new socio political era in Eastern Europe. Thereby the best answer is (D.)
Explanation:
