The correct answer is A. Korba.
Korba is a district in the Indian state of Chhattisgarh. It is the largest district in the state in terms of area and population. The district is known for its coal production. The Korba Coalfield is one of the largest coalfields in India. The coalfield is located in the Korba district and is spread over an area of about 1,500 square kilometers. The coalfield is owned and operated by the South Eastern Coalfields Limited (SECL). The SECL is a government-owned coal mining company. The Korba Coalfield produces about 25 million tonnes of coal per year. The coal from the Korba Coalfield is used to generate electricity and to produce steel.
The other options are incorrect.
Option B, Mand-Raigarh, is a district in the Indian state of Chhattisgarh. The district is not known for its coal production.
Option C, Sonhat, is a town in the Indian state of Chhattisgarh. The town is not known for its coal production.
Option D, Lakhanpur, is a town in the Indian state of Jammu and Kashmir. The town is not known for its coal production.