What Physical Process Is Happening Between Points B and C

What physical process is happening between points B and C?

A) Heat energy converts the solid water into liquid water.
B) Heat energy converts the liquid water into gaseous water.
C) Solid water is being heated, resulting in the temperature of the solid increasing.
D) Liquid water is being heated, resulting in the temperature of the liquid increasing.
E) Gaseous water is being heated, resulting in the temperature of the gas increasing.