According to Hess's law, the enthalpy change during a chemical reaction depends upon

According to Hess's law, the heat of reaction depends upon Initial and final conditions of reactants. The the heat of reaction is independent of the intermediate path of the reaction. For example, the heat of the reaction for the reaction $\mathrm{A}\to \mathrm{D}$ is equal to the sum of the heats of the reactions $\mathrm{A}\to \mathrm{B}$

$\mathrm{B}\to \mathrm{C}$

$\mathrm{C}\to \mathrm{D}$

Hence the correct answer is (C) the nature of the initial reactants and the final products.