Explanation:

- Option 1: Krishna Mohan Banerjee was an important figure in the Bengal Renaissance, but he did not found the Dharma Sabha.

- Option 2: Keshab Chandra Sen was a leader of the Brahmo Samaj and not involved in founding the Dharma Sabha.

- Option 3: Radhakanta Deb founded the Dharma Sabha in 1830. It was established to counteract social reforms supported by other groups such as the Brahmo Samaj.

- Option 4: Akshay Kumar Datta was involved with the Brahmo Samaj movement and had no connection to the Dharma Sabha.