Explanation:

Let’s break it down:

- Option 1: I.P. Desai

He’s known for his work on Indian family structure, but not particularly for regional studies of family and kinship.

- Option 2: K.M. Kapadia

Kapadia focused on Hindu marriage and family, but more from a general and historical viewpoint, not regional comparison.

- Option 3: A.M. Shah

Shah researched Indian family and household patterns but is not famous for a comprehensive regional study.

- Option 4: Irawati Karve

Irawati Karve stands out because she did exactly what the question asks—she compared family and kinship systems across Indian regions in her famous book _Kinship Organization in India_. She specifically analyzed differences and similarities among various communities across India.

So you picked Irawati Karve, and that’s spot on.