Ans.
Human body gets energy by the breakdown of complex organic molecules, such as carbohydrates, proteins, and fat molecules by the process of respiration. During respiration, energy is released in the form of ATP, which is used for the various metabolic functions.
The primary source for the energy is carbohydrate molecules, followed by lipids. When all the available carbohydrates and fats are used in respiration, some amino acids present molecules are used as source of energy.
Thus, the correct option). is 'carbohydrates, lipids, proteins.'