Explanation:

Let’s break this down clearly:

- Option 1: H. Risley

- He’s the main figure behind the racial theory of the caste system in India.

- Risley argued that caste divisions were due to racial differences, especially between Indo-Aryans and Dravidians.

- This was a British colonial-era idea, linking physical differences to social hierarchy.

- Option 2: Mazumdar

- D.N. Mazumdar was an Indian sociologist and anthropologist.

- He did study topics related to caste, but he didn’t really push the racial origin theory.

- His explanations were broader—he looked at caste as a social and cultural formation, not a racial one.

- Option 3: Both of them

- Based on history, only Risley is known for propounding the racial theory, not Mazumdar.

- Option 4: None of them

- Not true, since Risley did propose the racial theory.

So, here’s the thing:

Option 1: H. Risley is correct.