biosphere to lithosphere atmosphere to lithosphere hydrosphere to atmosphere biosphere to atmosphere
I gave my students this multiple choice question: Carbon cycles through several Earth subsystems. Which sequence most directly leads to the cycling of carbon that can result in the formation of petroleum?

Only one answer is correct among these 4 choices:
- biosphere to lithosphere
- atmosphere to lithosphere
- hydrosphere to atmosphere
- biosphere to atmosphere

Could you tell me which one is correct?

biosphere to lithosphere