The area demarcated as 'Damin-i-Koh' was declared to be the land of the ________ by British.

Santhals

The correct answer is Option (3) → Santhals

During the British colonial rule in India, there was a classification system for land and communities for administrative and revenue purposes. The term "Damin-i-Koh" refers to the hilly and forested areas in the Chotanagpur Plateau region. These areas were primarily inhabited by the indigenous tribal community known as the "Santhals."

The British colonial administration categorized different land areas based on their assessment of the local population and land-use patterns. In the case of the Damin-i-Koh area, it was declared to be the land of the Santhals, recognizing their traditional presence in those hilly and forested regions. This classification often had implications for land revenue and administration in these areas, as different land-use and ownership rights were established based on the categorization of the land and its inhabitants.

So, the correct option is [3].