The correct answer is C. Mines.
Chotanagpur is a plateau region in eastern India. It is known for its rich mineral resources, including coal, iron ore, and manganese. The mining industry has been a major driver of economic growth in Chotanagpur for many years.
Agriculture is also an important sector of the economy in Chotanagpur. The region is home to a number of different crops, including rice, wheat, and maize. However, agriculture is not as important as mining in terms of economic output.
Forests are also found in Chotanagpur. However, the forest cover in the region has declined in recent years due to deforestation.
Industries are not as developed in Chotanagpur as they are in other parts of India. However, there are a number of small and medium-sized industries in the region.
In conclusion, the economy in Chotanagpur is primarily based on mines. Agriculture, forests, and industries are also important sectors of the economy, but they are not as important as mining.