The question asks about a leader who was a close associate of Mahatma Gandhi and led a significant protest during the Civil Disobedience Movement in the Madras Presidency. Let's explore the background of this historical event to identify the correct answer.

During the Civil Disobedience Movement, one of the key events was the Salt March (or Dandi March) led by Mahatma Gandhi in March 1930, protesting the British monopoly on salt. The movement inspired many leaders across India to organize similar protests in their respective regions.

In the Madras Presidency, C. Rajagopalachari, a prominent Indian leader and close associate of Mahatma Gandhi, organized a salt march from Thiruchirapalli to Vedaranyam. This protest mirrored Gandhi's Satyagraha in Gujarat and was a pivotal moment in Tamil Nadu's participation in the national struggle against British rule.

Let’s examine the options:

• Sarojini Naidu: An important freedom fighter and poet, but not associated with leading any protest in the Madras Presidency during the Civil Disobedience Movement.
• Sardar Vallabhbhai Patel: A key leader in the Indian independence movement, known for organizing the Bardoli Satyagraha but not linked to the Madras Presidency’s protest.
• C. Rajagopalachari: Correct. He led the Salt Satyagraha in the Madras Presidency, demonstrating his strong association with Gandhi’s methods.
• K. Kamaraj: An influential leader from Tamil Nadu but not directly involved in this specific protest during the mentioned movement.

The most appropriate answer is C. Rajagopalachari, as he played a significant role in leading the protest in the Madras Presidency during the Civil Disobedience Movement.