Context: Schist can form when a rock is changed by high temperature and pressure. This piece of schist formed from a sedimentary rock.
Schist forms deep below the earth's surface. Schist is made of minerals such as mica, chlorite, and graphite.
What type of rock is schist?
A. igneous
B. sedimentary
C. metamorphic
Answer with the option's letter from the given choices directly.

C