The correct answer is Ramgarh.
Ramgarh was a princely state in India during the British Raj. It was located in the present-day state of Jharkhand. The state was founded in the 16th century by the Manjhi dynasty. The capital of the state was Ramgarh town.
The state of Ramgarh included the rich coal belt region in what is now the state of Jharkhand. The coal belt region is one of the most important coal-producing regions in India. The coal from this region is used to generate electricity and to produce steel.
The other options are incorrect. Jharia is a town in the Indian state of Jharkhand. It is located in the coal belt region. Sonbarsa is a town in the Indian state of Bihar. It is located in the coal belt region. Rajnagar is a town in the Indian state of Madhya Pradesh. It is not located in the coal belt region.