Enthalpy of a substance is defined as

• A. The sum of internal energy and the work done in forcing unit mass of substance into an enclosure at the constant pressure at which the substance exists
• B. Sum of sensible heat + latent heat of substance
• C. Total heat content of substance above zero degree centigrade
• D. Sensible heat of water + work done in forcing unit mass of substance into an enclosure at constant pressure at which the substance exists
• E. None of the above