The correct answer is A) Anti-colonial struggle.
P. Krishna Pillai and A.K. Gopalan were both leaders of the Communist Party of India. They played a key role in linking worker and peasant movements with the broader anti-colonial struggle. They argued that the working class and peasantry were the most oppressed sections of society and that they had a common interest in overthrowing British rule. They also argued that the anti-colonial struggle could not be successful without the participation of the working class and peasantry.
The demand for Dravida Nadu was a political movement that sought to create a separate state for the Dravidian people of South India. The social reform initiatives were a series of reforms that sought to improve the lives of the lower castes and women in India. The temple entry movements were a series of movements that sought to allow lower castes and women to enter Hindu temples.
P. Krishna Pillai and A.K. Gopalan were not involved in the demand for Dravida Nadu, the social reform initiatives, or the temple entry movements. They were focused on the anti-colonial struggle.