Answer:
C. It caused traffic on the Mississippi River to come to a halt
The Russian Revolution took place in 1917, during the final phase of World War I. It removed Russia from the war and brought about the transformation of the Russian Empire into the Union of Soviet Socialist Republics (USSR), replacing Russia's traditional monarchy with the world's first Communist state.
This is true. They took jobs in the north in factories for low wages. This increased the amount of industiralized areas. True.