Correct Option (d):
Anthracite is the highest rank of coal, distinguished by its highest carbon content, typically exceeding 90%. It is a hard, dense, and lustrous coal with low volatile matter content. Upon combustion, it produces a clean, smokeless flame and offers high heat output, making it suitable for specific industrial applications.
Incorrect Options:
Bituminous coal: This is an intermediate rank of coal, commonly used in thermal power generation. Its carbon content generally ranges from 60% to 80%.
Lignite: Known as brown coal, lignite is a lower rank of coal. It is characterized by high moisture content and a carbon percentage usually between 45% and 55%.
Peat: Representing the initial stage of coal formation, peat is composed of partially decomposed plant material. It possesses the lowest carbon content among the options, approximately 40%, and has a very high moisture level.