Compared to human milk, commercially prepared infant formula is:

Commercially prepared infant formula is indeed higher in protein and iron compared to human milk, primarily because formulas are specifically designed to meet infants' nutritional needs that may not be fully provided by breast milk alone, especially in terms of iron. Moreover, while human milk contains antibodies and other immunological factors that help protect infants from infections and diseases, formula lacks these bioactive components, which means it does not provide the same level of immune support as breast milk. The formulation of infant formulas allows for a balance of nutrients that can support growth and development while addressing the specific needs for protein and iron.

In contrast, the other options do not accurately reflect the differences between human milk and formula. While it is true that formula may sometimes have different carbohydrate and fat compositions, it is generally designed to mimic the nutritional profile of human milk closely. Vitamins and minerals in infant formula are tailored to meet dietary requirements, and while they may differ, they are not universally lower. The digestibility of formula can vary, but it is developed to be accessible to infants, which might not necessarily make it more digestible than breast milk. Thus, while all options have some truth to them, option B accurately emphasizes the nutritional contributions of formula in relation to its lack of immunological factors.