coal, oil, and gas. coal, shale, and quartz. shale, quartz, and coal. oil, shale, and granite.
I gave my students this multiple choice question: Decayed prehistoric plants have helped in the formation of

Only one answer is correct among these 4 choices:
- coal, oil, and gas.
- coal, shale, and quartz.
- shale, quartz, and coal.
- oil, shale, and granite.

Could you tell me which one is correct?

coal, oil, and gas.