Here's a problem to solve: Limestone is a sedimentary rock and marble is a metamorphic rock. Even though limestone and marble have the same chemical makeup, they are classified as different rocks because they

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

- A: were formed from different fossils
 
- B: took different amounts of time to form
 
- C: formed at different times
 
- D: formed by different methods
 