Answer:
D
Explanation: A is incorrect because the rivers were good for farming and made trade very easy. B is incorrect because the fact that the rivers flooded regularly is the reason the soil was rich enough to grow so many crops, as a matter of fact, the Nile river had such good flooding it was a tradition to celebrate and praise the Nile river by singing songs, holding festivals and bringing peace offerings .C is incorrect because the rivers made it easy for people to travel so it wouldn't make a good defense. The fact that the rivers flooded is what made it easy to grow crops and irrigate them, Mesopotamia achieved this by draining swamp-like lands and building canals.