The correct answer is: a) Imposition of Hindi as the national language.
The anti-Hindi agitations were a series of protests that took place in India in the 1960s and 1970s against the imposition of Hindi as the national language. The protests were led by non-Hindi speaking states, who felt that the imposition of Hindi would marginalize their languages and cultures. The protests were successful in delaying the imposition of Hindi as the national language, and in ensuring that English would continue to be used as a link language.
Option b) is incorrect because the anti-Hindi agitations were not primarily about economic policies. The protests were about the imposition of Hindi as the national language, and not about the economic policies of the central government.
Option c) is incorrect because the anti-Hindi agitations were not primarily about cultural suppression. The protests were about the imposition of Hindi as the national language, and not about cultural suppression.
Option d) is incorrect because the anti-Hindi agitations were not primarily about border disputes. The protests were about the imposition of Hindi as the national language, and not about border disputes.