Social Problems In India

Step 1: Understanding caste movements.
Caste movements are social movements aimed at addressing issues related to the caste system. These movements fought against the hierarchical and oppressive structure of the caste system and promoted equality and social justice.
Step 2: Explanation of the Satyashodhak movement.
The Satyashodhak movement, led by Jyotirao Phule, aimed at the social upliftment of the lower castes and the abolition of untouchability. It was a prominent caste reform movement in India.
Step 3: Explanation of other options.

- The Indigo movement was a protest against the exploitation of indigo farmers by the British.
- The Trade Union movement focused on workers' rights.
- The Chipko movement was an environmental movement focused on forest conservation.
Step 4: Conclusion.
Thus, the correct answer is Satyashodhak movement, as it was a caste reform movement.