Here's a problem to solve: Coal is usually found underground, compressed in a layer between other types of rock. Coal is produced by what rock-forming process?

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

- A: crystallization from melted rock
 
- B: formation of sediment from weathering
 
- C: deposition and burial of dead plant matter
 
- D: eruption of volcanic ash followed by settling in a layer
 