Context: This is a piece of tillite. It formed from a type of sediment called till. Till is made up of grains of various sizes, from mud to boulders. The grains are often uneven in shape.
Till is deposited by glaciers as they melt. Many layers of till can build up at the mouth of a glacier. Tillite forms when these layers are pressed together to form rock.
What type of rock is tillite?
A. igneous
B. sedimentary
C. metamorphic
From the given choices, select the correct answer and reply with the letter of the chosen option.

B