Which social reformer is associated with the idea of 'one caste, one Religion, one God for all man'?

Sri Narayan Guru

The correct answer is Option (3) → Sri Narayan Guru

Sri Narayana Guru, born in Kerala, preached brotherhood for all and fought against the ill effects of the caste system. He led a quiet but significant social revolution and gave the watchwords ‘One Caste, One Religion, One God for all men’