Solution:R.S. Sarkar, a physical anthropologist, is known for classifying the Indian population primarily and solely on the basis of the cephalic index. His approach focused heavily on cranial measurements, especially the ratio of the maximum breadth to the maximum length of the skull, known as the cephalic index.Unlike Guha and Eickstedt who used multiple somatometric features (e.g., skin color, hair form, stature, nasal index), Sarkar limited his classification mainly to cranial dimensions, emphasizing a simplified racial typology. His studies contributed to dividing Indian populations into groups like brachycephalic, mesocephalic, and dolichocephalic types, similar in methodology to Risley but carried out more systematically in post-colonial Indian anthropological research.
Therefore, although Risley is more popularly known for early racial classification using the cephalic index, Sarkar's work is specifically recognized for using only the cephalic index in his academic classification model, distinguishing his method from others who used composite traits.