Answer: (Detailed Solution Below)
Option D: 80 per cent
Detailed Solution:
The correct answer is “80 per cent”.
The Chota Nagpur Plateau is located in eastern India and covers parts of five states: Jharkhand, Chhattisgarh, Odisha, West Bengal, and Bihar. These states collectively have around 150,000 metric tonnes of coal against a total of 187,105 metric tonnes in all of India. So, the Chota Nagpur Plateau accounts for about 80% of India's coal reserves based on this data.