The correct answer is c) exothermic process.
An exothermic process is characterized by the release of energy, usually in the form of heat, as the reactants transform into products. In this case, when the products have lower energy than the reactants, it indicates that energy has been released during the reaction. This is often observed in combustion reactions and many oxidation reactions.
In contrast, an endergonic process (option a) requires an input of energy and results in products that have higher energy than the reactants. Similarly, an endothermic process (option b) absorbs energy, leading to an increase in the energy of the products compared to the reactants. Thus, the significant difference lies in how energy is managed during the reaction, with exothermic reactions being the process that lowers energy in the products.