The correct response is:
the products, because burning coal releases a significant amount of heat.
In the process of burning coal, a combustion reaction occurs, transforming the coal (the reactant) into gases (such as carbon dioxide and water vapor) and ash (a solid residue). During this exothermic reaction, energy is released in the form of heat, leading to a decrease in the overall energy of the reactants compared to the products. Thus, while coal starts with stored chemical energy, the combustion process results in the release of energy, meaning the products have less energy compared to the initial chemical energy of the coal before combustion.