Mathematics, mostly.
They also did groundbreaking work in the following fields:
Astronomy
Philosophy
Geography
Sciences
Technology
Answer:
I believe the answer might be B providing food for its people
He served as the General Secretary of the Central Committee of the Communist Party of the Soviet Union from 1922 until his death in 1953. In the years following the death of Vladimir Lenin, he rose to become dictator of the Soviet Union, using a combination of manipulation and terror to destroy his opposition.
