Who represented the Tribal population in the Constituent Assembly?

Jaipal Singh.

The correct answer is Option (3) → Jaipal Singh

Jaipal Singh was a representative of the tribals in the Constituent Assembly.

One of the groups mentioned by Ranga, the tribals, had among its representatives to the Assembly the gifted orator Jaipal Singh. 

Singh spoke eloquently on the need to protect the tribes, and ensure conditions that could help them come up to the level of the general population. Tribes were not a numerical minority, he argued, but they needed protection. They had been dispossessed of the land they had settled, deprived of their forests and pastures, and forced to move in search of new homes. Perceiving them as primitive and backward, the rest of society had turned away from them, spurned them. He made a moving plea for breaking the emotional and physical distance that separated the tribals from the rest of society: “Our point is that you have got to mix with us. We are willing to mix with you … ”. Singh was not asking for separate electorates, but he felt that reservation of seats in the legislature was essential to allow tribals to represent themselves. It would be a way, he said, of compelling others to hear the voice of tribals, and come near them.