The correct answer is: Anthracite.
Anthracite is the highest quality of hard coal. It is a hard, black coal with a high carbon content. It is the most mature type of coal and has a high heat content. Anthracite is used in power plants and for industrial purposes.
Bituminous coal is a soft, black coal with a high carbon content. It is less mature than anthracite and has a lower heat content. Bituminous coal is used in power plants, for industrial purposes, and for making coke.
Lignite is a soft, brown coal with a low carbon content. It is the least mature type of coal and has the lowest heat content. Lignite is used in power plants and for making coke.
Peat is a soft, brown material that is formed from partially decomposed plant material. It is not a true coal and has a very low heat content. Peat is used as a fuel in some areas and as a soil amendment.