A.P. world history question?

The answer is D however it is disputed by many scholars. the elephant is native to India so e is not the answer. A is not the answer because the Aryans Were not farmers but raised cattle, they had no written record and this is why there is so much debate as to wghat really happened here so B is not the answer and C is not the answer Because They believed in many Gods some of which were war like and basis for the belief that they created a caste system resulting in your answer...D