The correct answer is Sardar Bhagat Singh .

The person who changed the name of Hindustan Republic Association established by Sachindra Nath Sanyal to Hindustan Socialist Republican Association was Sardar Bhagat Singh. He was one of the most prominent leaders of the Indian independence movement and a revolutionary socialist. He was influenced by the ideas of Karl Marx and Lenin and believed in the establishment of a socialist society in India.

Bhagat Singh, along with his associates, formed the Hindustan Republican Association (HRA) in 1924, which later changed its name to the Hindustan Socialist Republican Association (HSRA) in 1928. The objective of the HSRA was to establish a socialist republic in India through armed revolution. The organization was involved in several revolutionary activities, including the Kakori Train Robbery and the bombing of the Central Legislative Assembly in Delhi.

Bhagat Singh believed that socialism was the only solution to the problems faced by India and that political independence alone was not enough. He emphasized the need for a socialist revolution to overthrow the British colonial rule and the exploitative capitalist system in India. The slogan “Inquilab Zindabad” was often used by him and his associates as a call for revolution and was popularized during the Indian independence movement.