Concept:Latent heat is the thermal energy involved in changing the state of a substance without changing its temperature.Explanation:When a substance changes state, such as melting, boiling, or freezing, it absorbs or releases thermal energy.This energy does not cause a temperature change; it is used to break or form intermolecular bonds.Therefore, the thermal energy added or removed during a change of state is called latent heat.Answer:Option A. latent heat