Which of the following describes an exothermic reaction?

An exothermic reaction is characterized by the release of heat to the surroundings. During such a reaction, the energy required to break the bonds in the reactants is less than the energy released when new bonds form in the products. As a result, the excess energy is released in the form of heat, resulting in a temperature increase in the surroundings. This heat release can be measured and is what distinguishes exothermic reactions from endothermic ones, which absorb heat.

In this context, the other options do not align with the definition of exothermic reactions: the absorption of heat from surroundings describes an endothermic reaction, the higher enthalpy of products compared to reactants implies energy input rather than release, and the mention of high temperatures leading to spontaneous processes does not capture the essence of exothermicity. Therefore, the correct characterization of an exothermic reaction is that it releases heat to the surroundings.