Hint: Here, we will discuss coal and its qualities. So, what is coal mining?Coal mining is the method of extracting coal from the bottom. Coal is classed into four main varieties, or ranks: anthracite coal, bituminous, sub hydrocarbon, and coal. Coal is primarily used as fuel to generate electricity in the United States. The coal is burned and also the heat given off is employed to convert water into steam, that drives a rotary engine.
So, the superior quality coal is called Anthracite. Anthracite, additionally referred to as anthracite coal, is a hard, compact variety of coal that includes a sub metallic luster. It has the best carbon content, the fewest impurities, and also the highest energy density of all kinds of coal and is that the highest ranking of coals. High grade (HG) and radical high grade (UHG) hard coal are the best grades of anthracite. They’re the purest sorts of coal, having the best degree of coalification, the best carbon count and energy content and also the fewest impurities (moisture, ash and volatiles).
Anthracite is the most metamorphosed variety of coal (but still represents inferior metamorphism), during which the carbon content is between 86%-98%. The term is applied to those forms of coal that don't provide off tarry or different organic compound vapors’ once heated below their purpose of ignition. Hard coal ignites with issue and burns with a brief, blue, and smokeless flame.
Hence, the correct answer is option (C).
Note:Anthracite is classified into customary grade that is employed primarily in power generation and high grade (HG) and extremist high grade (UHG), the principal uses of that area unit within the science sector. Anthracite accounts for about 1%of global coal reserves, and is mined in exactly a couple of countries around the world. China accounts for the bulk of worldwide production; different producers are unit Russia, Ukraine, North Korea, African country, Vietnam, the UK, Australia, North American country and therefore in the U.S..Total production in 2010 was 670 million tons.