Which rock is comprised of mostly carbon, as well as, sulfur, hydrogen, oxygen, nitrogen, and ash?

A) basalt

B) coal

C) schist

D) slate

The correct answer is: B) coal.

Coal is a sedimentary rock black or brown color composed of carbon with variable amounts of other elements such as hydrogen, sulfur, oxygen, and nitrogen. The formation of coal goes through two steps: decay of dead plant matter into peat and conversion of peat into coal under the influence of heat and pressure of deep burial.