Answer:
A. boiling point
Explanation:
The correct answer is;
A. boiling point
The boiling point of a liquid is the temperature at which the vapour pressure is equal to the atmospheric pressure.
B. melting point
This option is wrong because the melting point is the temperature at which a solid undergoes a phase change to a liquid.
C. freezing point
This option is wrong because the freezing point is the temperature at which a liquid undergoes a phase change to a solid.