seas that have evaporated. natural gas subjected to heat. melted and cooled metamorphic rock. plant remains decomposed under pressure.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Coal is formed from
Possibilities:
- seas that have evaporated.
- natural gas subjected to heat.
- melted and cooled metamorphic rock.
- plant remains decomposed under pressure.

plant remains decomposed under pressure.