Which of the following is the best definition of hess' law?

a. heat evolved in a given process can be expressed as the sum of the heats of several processes that, when added, yield the process of interest.
b. the enthalpy of a process is the difference between the enthalpy of the products and the enthalpy of the reactants.
c. since enthalpy is a state function, it will be different if a reaction takes place in one step or a series of steps.
d. at constant pressure the enthalpy change of a reaction is equal to the heat change of a reaction.
e. heat is always released by the decomposition of 1 mole of a compound into its constitute elements.