Question: What is the main ethnic group of the Indian state where the Centre for Studies in Social Sciences, Calcutta is located?
Sentence (from "West Bengal"): A part of the ethno-linguistic Bengal region, it is bordered by Bangladesh in the east, and Nepal and Bhutan in the north; it shares borders with five Indian states: Odisha, Jharkhand, Bihar, Sikkim, and Assam.
Relevant evidence: No