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

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

anonymous · Answer

I believe it might be B. http://en.wikipedia.org/wiki/Soviet_atomic_bomb_project#Espionage

anonymous · Answer

Okay thank you

zale101 · Answer

i agree with @Chuvak it is B
read about Klaus Fuchs and what he did