The correct answer is: a) Hindustan Socialist Republican Association (HSRA).
Bhagat Singh was a revolutionary socialist who was associated with the Hindustan Socialist Republican Association (HSRA). The HSRA was a revolutionary organization that was founded in 1928 by Chandrashekhar Azad, Bhagat Singh, Sukhdev Thapar, and Rajguru. The HSRA was committed to overthrowing British rule in India through armed struggle.
The Ghadar Party was a revolutionary organization that was founded in 1913 by Lala Hardayal, Sohan Singh Bhakna, and Taraknath Das. The Ghadar Party was committed to overthrowing British rule in India through armed struggle. However, the Ghadar Party was disbanded in 1915 after the failure of the Ghadar Mutiny.
The Indian National Congress was a political organization that was founded in 1885 by Allan Octavian Hume. The Indian National Congress was committed to achieving independence for India through non-violent means.
The Muslim League was a political organization that was founded in 1906 by Nawab Salimullah Khan. The Muslim League was committed to protecting the rights of Muslims in India.