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

The correct answer is B) C. Rajagopalachari. In April 1930, Rajaji led a satyagraha march from Tiruchirappalli to Vedaranyam on the Tanjore coast, where he made salt in defiance of the government salt monopoly. The march began on 13 April and reached the coast in the last week of April, which is why it is known as the Vedaranyam Salt Satyagraha.

Why the others are wrong:

• V.O. Chidambaram Pillai was a Tuticorin leader known for the Swadeshi Steam Navigation Company and was jailed in 1908 for his Swadeshi activism. He was not the organiser of the salt march.
• K. Kamaraj took part as a young volunteer in the Vedaranyam satyagraha, but he was a participant, not the organiser of the march.
• Annie Besant led the Home Rule League and opposed Gandhi's non-cooperation line. She had no role in the 1930 salt satyagraha.

The core concept is the Salt Satyagraha as part of the Civil Disobedience Movement, launched after Gandhi's Dandi March. For Mains, it fits under modern Indian history on mass mobilisation and the regional spread of the national movement beyond Gujarat.

Trap: aspirants pick the most famous names by default, or confuse Kamaraj's participation with leadership.