In the diagram shown below, M and Q represent two states of matter. A rectangle labeled M has an arrow labeled Cooling which points from the rectangle M to a rectangle labeled Liquid. An arrow labeled Cooling points from the rectangle labeled Liquid towards the rectangle labeled Q.

What do M and Q represent?

M represents a solid and Q represents a gas.
M represents gas and Q represents a solid.
M represents a solid and Q represents liquid.
M represents a liquid and Q represents a gas.