Context: This is a piece of slate. Slate usually forms from a sedimentary rock called shale. Slate can form when shale is changed by high temperature and pressure.
Slate is usually dark-colored. The word blackboard comes from the color of slate. Decades ago, blackboards were made of black slate.
What type of rock is slate?
A. igneous
B. sedimentary
C. metamorphic
Identify the correct option from the choices provided and respond with the letter of the correct option.

C