Here's a problem to solve: Gas and oil come from deposits of petroleum deep within the earth. What caused these deposits to form?

Among the 4 following options, which is the correct answer?

- A: Rocks were dissolved by water.
 
- B: Lava deposited and then cooled.
 
- C: The remains of plants and animals were trapped.
 
- D: Air, water, and minerals combined.
 