Final answer:
Fats contain about 2.25 times more energy per unit of weight than carbohydrates or proteins, so the closest answer to the question is (b) 3.
Step-by-step explanation:
Fats, also known as lipids, store a significantly higher amount of energy per unit of weight compared to carbohydrates or proteins. This is reflected in caloric content, with one gram of fat providing approximately nine calories, while one gram of either carbohydrates or proteins provides around four calories. Thus, fats contain about 2.25 times more energy per unit of weight than do carbohydrates or proteins. Given the choices provided in your question, the closest correct answer would be (b) 3 times more energy per unit of weight, even though the exact multiple is slightly more than double.