Normal Boiling Point Is Defined as

Normal boiling point is defined as

A) the temperature at which the vapor pressure of a liquid equals 1 atm.
B) the pressure at which any liquid boils at 373.15 K.
C) the temperature at which water boils in a vacuum.
D) the temperature at which the liquid and gaseous phases of a substance have equal densities.
E) the temperature at which the enthalpy of vaporization equals 100.0 kJ/mol.