The correct answer is (c) Rajasthan.
Rajasthan has the largest reserves of lignite coal in India. The lignite coal reserves in Rajasthan are estimated to be around 28 billion tonnes. The lignite coal reserves in Gujarat are estimated to be around 1.5 billion tonnes. The lignite coal reserves in Kerala are estimated to be around 0.5 billion tonnes. The lignite coal reserves in Tamil Nadu are estimated to be around 0.3 billion tonnes.
Lignite coal is a type of coal that is formed from plant material that has been buried and subjected to heat and pressure for a relatively short period of time. Lignite coal is a lower-grade coal than bituminous coal or anthracite coal. Lignite coal is soft and has a high moisture content. Lignite coal is used to generate electricity and to produce coke.