Correct Option
Milk is recognized as a significant source of various essential nutrients beyond proteins and carbohydrates. It is particularly rich in calcium, which is vital for bone and teeth health, and potassium, essential for maintaining fluid balance, nerve signals, and muscle contractions. However, milk is not considered a significant dietary source of iron. The iron content in milk is relatively low, often necessitating supplementation, especially for vulnerable groups like infants and pregnant women.
Incorrect Options
Options (1), (3), and (4) are incorrect because they include iron as a significant nutritional element found in milk. While milk contains trace amounts of iron, its concentration is insufficient to classify it as a nutritionally significant source. Therefore, options suggesting the presence of iron in substantial quantities alongside calcium and potassium are factually inaccurate in the context of major nutritional contributions of milk.