Explanation:

- The concept of "hierarchy" in the context of caste stratification is most famously associated with L. Dumont.

- Louis Dumont (Option 4) in his book "Homo Hierarchicus" discussed how hierarchy is central to understanding the Indian caste system. He argued that caste is not just about separation but about a ranking of groups (hierarchy).

- T.N. Madan (Option 1) is a well-known Indian sociologist who has written about Indian society and kinship, but he did not introduce the concept of hierarchy in caste.

- Gopala Sarana (Option 2) is an Indian anthropologist, but not specifically associated with the hierarchy concept in caste studies.

- D.F. Pocock (Option 3) worked on Indian society, but the core theory of hierarchy in caste is credited to Dumont.

Option 4 - L. Dumont is the correct answer.