It is proposed that modern coal deposits mostly derive from the
Carboniferous period because

A)Algae in ocean surrounding the Pangea supercontinent settled
to the oxygen-poor depths, where it became petrified as coal

B)Plant cell walls in the extensive forests became petrified
because of sudden cooling and drying of the environment

C)Plants evolved lignocellulosic cells walls ~80 million before
white rot fungus evolved the ability to efficiently degrade these
structures

D)The warm wet climate supported the most prolific forests the
world has had

E)Ca2+ was more prevalent because of extensive weathering of
rock and volcano action, making plant cell walls stronger and more
resistant to degradation.