Correct Answer: atmospheric pressure

Solution : The correct option is atmospheric pressure.

The atmospheric pressure influences the boiling point of water. In simple terms, the boiling point is the temperature at which a liquid's vapour pressure equals atmospheric pressure. The boiling point of water fluctuates as the atmospheric pressure varies with height and weather conditions. Pure water boils at 100 degrees Celsius at normal atmospheric pressure (1 atm), which is frequently seen at or around sea level.