Here's a problem to solve: Students are observing two fossils in a lab. They are told by the teacher that the fossils were found in different rock layers. What can the students most likely determine from just observing the fossils?

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

- A: how each organism died
 
- B: the exact age of the fossils
 
- C: when the fossils were discovered
 
- D: the type of environment in which the organisms lived
 