Explanation:

- Option 1: Jyotiba Phule

- Jyotiba Phule was a social reformer and activist in the 19th century, known for his efforts in education and social equality, particularly regarding the upliftment of the backward classes. However, he was not involved with the Second Backward Classes Commission.

- Option 2: Bhim Rao Ambedkar

- Dr. B.R. Ambedkar was a prominent leader known for his work in drafting the Indian Constitution and advocating for the rights of Dalits. He played a crucial role in social reform but was not linked with the Second Backward Classes Commission.

- Option 3: BP Mandal

- Correct Answer: BP Mandal was the Chairman of the Second Backward Classes Commission, also known as the Mandal Commission, established in 1979 in India to assess the social and educational status of the backward classes.

- Option 4: Babu Jagjivan Ram

- Babu Jagjivan Ram was an esteemed Indian leader and politician who worked for the upliftment and rights of the Dalits; however, he was not the Chairman of the Second Backward Classes Commission.