The correct answer is C. Rajagopalachari.

C. Rajagopalachari, also known as Rajaji, organized a march on the Tanjore coast to break the Salt Law in April 1930. This march was a part of the Civil Disobedience Movement led by Mahatma Gandhi during the Indian independence struggle.

Rajaji, a prominent leader of the Indian National Congress and a close associate of Mahatma Gandhi, played an active role in various freedom movements and campaigns, including the Salt Satyagraha. The march on the Tanjore coast aimed to challenge the British-imposed Salt Law, which regulated the production, distribution, and sale of salt and was seen as a symbol of British oppression and control over Indian resources.

By organizing the march and openly defying the Salt Law, Rajaji and the participants aimed to raise awareness, mobilize public support, and challenge British authority. This act of civil disobedience was a significant step in the larger nonviolent resistance movement against British rule in India.

Therefore, the correct answer is C. Rajagopalachari.