The Santhal rebellion of 1855-56 was a significant event in the history of India, particularly for the tribals residing in the region. The rebellion ultimately led to the creation of a separate geographical entity known as Santhal Parganas for the tribals.

Option 1: Sidhu and Chakara - These two individuals were not directly associated with the Santhal rebellion.

Option 2: Chakara and Bogra - While Chakara was indeed one of the leaders associated with the rebellion, there is no mention of Bogra as a leader.

Option 3: Sidhu and Kanhu - This is the correct answer. Sidhu and Kanhu were the leaders closely associated with the Santhal rebellion. They played pivotal roles in organizing and leading the tribals in their resistance against the oppressive British rule.

Option 4: Dora and Chakara - Although Chakara was involved in the rebellion, there is no mention of Dora as a leader associated with the Santhal rebellion.

Overall, option 3, Sidhu and Kanhu, is the correct answer as these were the leaders who played significant roles in the Santhal rebellion of 1855-56.