What is happening to the acetic acid between points X and Y on the graph?
A.Solid acetic acid is being converted from a solid to a liquid by absorbing heat energy from the surroundings.
B.Liquid acetic acid is becoming warmer as it absorbs heat energy from the surroundings.
C.Liquid acetic acid is being converted from a liquid to a gas by absorbing heat energy from the surroundings.
D.Solid acetic acid is becoming warmer as it absorbs heat energy from the surroundings.