Who was the leader of the Santhal Revolt of 1855-56?

The correct option is Sidhu Manjhi.

The Santhal Revolt of 1855-1856 was a major rebellion in eastern India (in present-day Jharkhand and West Bengal) led by the Santhal tribal community against the oppressive system of the British East India Company and local zamindars (landlords).

The rebellion was spearheaded by four Murmu brothers: Sidhu, Kanhu, Chand, and Bhairav. Among them, Sidhu Manjhi (along with his brother Kanhu) was the primary leader who mobilized thousands of Santhals to fight against colonial exploitation.