How were floods a positive factor for ancient india?

The floods in ancient India left the land fertile to be filled and to have crops grown on. This is the same thing the Mesopotamians did.

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.