Answer: Option B
Step-by-step explanation:
Coal is formed million of years ago when the earth was covered with swamp forests where the plants, mosses and ferns grew.
The plants grew and die and then also the newer plants grow. As the time grew up more and more plants grow and die. They made a separate layer. One layer on the other. The water and dirt on the these layers made it compact.
The chemical reactions take place and heat and pressure converted the dead matter into coal because there was no oxygen left and the matter left was carbon.