Explanation:

- Let’s break it down: Louis Renou, Hocart, and Senart are each known for different takes on the caste system.

- Here’s where Senart stands out: He explained the origin of caste mainly through prohibitions around sacramental food. He said caste groups kept themselves apart by refusing to eat with others or accept food from certain hands.

- Hocart, on the other hand, didn’t focus on sacramental food. He emphasized hierarchy and ritual kingship instead.

- So, both of them didn’t use the food taboo as their central idea. Only Senart did.

Option 2 – Senart is correct.