Which one is the best and non smoky coal?

The answer is D: anthracite

Anthracite is a type of coal.Anthracite contains a high amount of fixed carbon—80 to 95 percent—and very low sulfur and nitrogen—less than 1 percent each. Volatile matter is low at approximately 5 percent, with 10 to 20 percent ash possible. Moisture content is roughly 5 to 15 percent.Anthracite is the highest grade of coal because it is the hard coal and contains over 90per cent of carbon and also it is the last step of formation of coal.

Anthracite coal is the better choice when considering your next heating or supplemental heating resource. Anthracite Coal burns HOTTER than other fossil fuels. All resources that are burned as fuels or used to generate heat are measured by the British Thermal Unit, also known as BTUs.Anthracite is a chalky and earthy near-black or very dark gray. Anthracite itself is a form of coal used in thermal power stations for generating electricity.Different coal types are all minerals and rocks made largely of carbon. This fossil fuel generates ~40% of the world's electricity and about 25% of the world's primary energy.

The ranks of coal (from most to least carbon content) are as follows: anthracite, bituminous coal, sub-bituminous coal, and lignite. The coal with the highest carbon content is the best and cleanest type of coal to use.