Here's a problem to solve: Geologists have identified seven major tectonic plates at the surface of Earth. Which evidence best indicates that tectonic plates collide?

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

- A: Wind erodes surface rock formations.
 
- B: Fossils date back thousands of years.
 
- C: Small rocks are left behind when glaciers retreat.
 
- D: Older layers of rock are located above newer layers of rock.
 