Explanation:

- The concept of “unitary coded substance” refers to the idea that a person’s body is constituted of a single, pure substance, making any contact with pollution a threat to their ritual purity.

- This concept was primarily used by McKim Marriott and R.B. Inden in their studies of Hindu society to explain pollution and purity.

- Pauline Kolenda wrote extensively on purity and pollution but did not directly use the term “unitary coded substance.”

- M.N. Srinivas is known for the concept of Sanskritization, not unitary coded substance.

- T.N. Madan has contributed to the sociology of religion but not specifically this concept.

Option 2: McKim Marriott and R.B. Inden is the correct answer.