The correct answer is: a) Imposition of Hindi as the national language.
The anti-Hindi agitations in Tamil Nadu were a series of protests that took place in the Indian state of Tamil Nadu from 1965 to 1968. The protests were against the imposition of Hindi as the national language of India. The protesters argued that Hindi was not the language of the majority of Indians and that it would be unfair to impose it on the people of Tamil Nadu. The protests were largely successful in preventing Hindi from being imposed as the national language.
Option b) is incorrect because the economic policies of the central government were not a major issue in the anti-Hindi agitations. The protesters were primarily concerned with the imposition of Hindi, not with the economic policies of the central government.
Option c) is incorrect because cultural suppression was not a major issue in the anti-Hindi agitations. The protesters were primarily concerned with the imposition of Hindi, not with cultural suppression.
Option d) is incorrect because border disputes were not a major issue in the anti-Hindi agitations. The protesters were primarily concerned with the imposition of Hindi, not with border disputes.