Question

Which of these helped the Soviet Union develop nuclear capabilities?

scientific data provided by Earth-orbiting satellites
information provided by spies in the United States
classified documents left behind by the U.S. military in Korea
plans provided to the International Atomic Energy Commission

Answer 1

http://en.wikipedia.org/wiki/Soviet_atomic_bomb_project

"The Soviet Union benefited from highly successful espionage efforts on the part of the Soviet military intelligence (GRU). "

Answer 2

C and D are definitely wrong as both happened after the soviet union developed their first nuclear weapons

Answer 3

So it was B? because Ethel and Julius Rosenberg were the spys?

Answer 4

They were one of many spies. B seems right, yeah