Which of the following best describes an exothermic reaction?

An exothermic reaction is characterized by the release of heat to the surrounding environment. When such a reaction occurs, the energy stored in the reactants is transformed into products, and the excess energy is released as heat. This release of heat raises the temperature of the surroundings, which is a key indicator of an exothermic process.

For example, combustion reactions, where fuels react with oxygen, are classic examples of exothermic reactions that produce heat and can significantly increase the temperature of nearby materials. This is why the option indicating that an exothermic reaction releases heat and causes the temperature of the surroundings to increase is the most accurate description of the phenomenon.