Which of the following is NOT a macronutrient?

Vitamins are classified as micronutrients, which are essential for various biochemical functions in the body but required in smaller amounts compared to macronutrients. Macronutrients, on the other hand, include fats, carbohydrates, and proteins, all of which are needed in larger quantities for energy, growth, and maintenance of body functions. Fats provide a concentrated source of energy and are important for nutrient absorption; carbohydrates are the body's primary energy source; and proteins play critical roles in building and repairing tissues, as well as in enzyme and hormone production. Therefore, the distinction lies in the amount required and their functional roles in nutrition, making vitamins the correct response to the question of which is not a macronutrient.