Which one of the following statements accurately describes how coal is formed?
a) Limestone is subjected to extreme heat and pressure.
b) Sunlight, minerals, water, and soil combine to form the black rock known as coal over many thousands of years.
c) Ancient dead plant matter is buried in swamps, prevented from fully decaying, and subjected to extreme heat and pressure by layers of material above it.
d) Microscopic organisms in oceans or lakes die and are buried in an environment that prevents decay and subjects the material to extreme heat and pressure over hundreds of millions of years.
