I’m the illustration, which site is an example of a trench

The answer would be:

C

If you'd like to know why:

Ocean trenches are made when two oceanic plates CONVERGE. This is what we call convergent boundary, which is the process where two plates collide. When this happens, the less dense plate subducts or goes under the other plate. The point where the plate goes under is marked by a trench.  

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation: