Explanation:

- The Poona Pact of 1932 was indeed an agreement specifically between Mahatma Gandhi and BR Ambedkar.

- Signed on September 24, 1932, the pact aimed to address the issue of separate electorates for the Dalits (then referred to as 'Depressed Classes') in the Indian Legislative Assembly.

- Option 1: BR Ambedkar was a key leader for the Dalits and played a major role in negotiating the terms of the pact.

- Option 2: Lord Irwin was the Viceroy of India during an earlier period, but not involved in this agreement.

- Option 3: Aurobindo Ghose was a spiritual leader and freedom fighter, not linked to the Poona Pact.

- Option 4: Bal Gangadhar Tilak was an early nationalist leader but had passed away by 1920, well before the Poona Pact.