The major source of fruits and vegetables in the soviet union under communism were

From the command economy.   

Five year plan.  

Most sadly failed.  It's hard to command what people want and not want.  

The answer is c, i, iii, and iv. this is because farming and mining deal with harvesting raw materials, construction work falls under manufacturing, and piloting a plane is a service. ii is wrong because making bread is using  raw materials to produce goods, which would fall under the secondary sector, not primary.

Cthat is the answer