ANS:D - None of these

The term "mass transfer co-efficient" is typically associated with units such as mass transfer coefficient (m/s), kg/m²s, or mol/m²s. Therefore, if we're looking for a term that is not a unit of mass transfer coefficient, the correct answer would be: enthalpy (J/mol) Enthalpy is a thermodynamic property that represents the internal energy of a system plus the product of its pressure and volume. It is not a unit of mass transfer coefficient.