The correct answer is (c), Jharia.
Jharia is the largest coalfield in India, located in the state of Jharkhand. It is estimated to contain about 3 billion tonnes of coal, making it one of the largest coal reserves in the world. The coalfield has been in production since the 18th century, and is currently operated by Coal India Limited.
Raniganj is the second largest coalfield in India, located in the state of West Bengal. It is estimated to contain about 2 billion tonnes of coal. The coalfield has been in production since the 19th century, and is currently operated by Eastern Coalfields Limited.
Bokaro is the third largest coalfield in India, located in the state of Jharkhand. It is estimated to contain about 1 billion tonnes of coal. The coalfield has been in production since the 20th century, and is currently operated by Bokaro Steel Plant.
Giridih is the fourth largest coalfield in India, located in the state of Jharkhand. It is estimated to contain about 0.5 billion tonnes of coal. The coalfield has been in production since the 19th century, and is currently operated by Central Coalfields Limited.