The temperature of an object is an indicator of the average kinetic energy of its molecules; option [D]. It represents the measure of the average energy associated with the random motion of molecules within the object. This kinetic energy determines the object’s temperature, which can be measured using various scales such as Celsius or Kelvin. The temperature reflects the distribution of kinetic energies among the molecules, providing valuable information about the thermal state of the object. Therefore, the correct option is [D] The average kinetic energy of its molecules, as temperature directly correlates with the average kinetic energy of the particles within the object. This fundamental relationship between temperature and kinetic energy is crucial in understanding the behavior of matter and its thermal properties, influencing various physical and chemical processes in nature and technology.