Answer:
C. freezing
Step-by-step explanation:
Point B is right at the border between a solid and a liquid so you can have two physical changes:
a) solid is meting to transform into a liquid
or
b) liquid is freezing to transform into a solid (C)
If you are on the border between a solid and a gas you have the following physical changes:
solid to gas - sublimation
gas to solid - deposition
If you are on the border between a liquid and a gas you have the following physical changes:
liquid to gas - boiling
gas to liquid - condensation