Who of the following organized a march on the Tanjore coast to break the Salt Law in April 1930?

The correct option/answer is C. Rajagopalachari.

Explanation:
During the Civil Disobedience Movement in 1930, Mahatma Gandhi led the historic Dandi March to protest against the British salt monopoly. Inspired by this event, nationalist leaders in different parts of India organized similar salt marches.

In the Madras Presidency (modern-day Tamil Nadu), the veteran Congress leader C. Rajagopalachari (popularly known as Rajaji) organized and led a march from Trichinopoly (now Tiruchirappalli) to Vedaranyam on the Tanjore coast. The march took place in April 1930, ending with the symbolic breaking of the Salt Law on April 30, 1930. This campaign is famous in history as the Vedaranyam Salt Satyagraha.