Correct Option: C

The heat content of anthracite ranges from 22 to 28 million Btu per short ton (26 to 33 MJ/kg) on a moist, mineral-matter-free basis. Anthracite (“coallike”) is a hard, compact variety of mineral coal that has a high luster. It has the highest carbon content, the fewest impurities, and the highest calorific content of all types of coals, which also include bitu-minous coal and lignite. Anthracite is the most metamorphosed type of coal (but still represents low-grade meta-morphism), in which the carbon content is between 92.1% and 98%.