Which one of the following statements about the Principle of Calorimetry is correct ?

The Principle of Calorimetry (also known as the Law of Mixtures) is a restatement of the Law of Conservation of Energy in the context of thermal physics. It states that when two bodies at different temperatures are brought into contact within an isolated system, the heat lost by the hot body is equal to the heat gained by the cold body (Heat Lost = Heat Gained). Since the conservation of energy is a fundamental law of the universe, this principle is considered always valid within the scope of its definition (an isolated system). It applies regardless of whether the substances undergo a change in temperature (using specific heat, Q = mcΔT) or a change of state (using latent heat, Q = mL). It does not require temperature to be constant, nor is it limited to specific phases of matter.