What is the role of zinc in the diet?

Zinc is an essential trace mineral that plays a critical role in several bodily functions, making option B the correct answer. It is integral to supporting the immune system by helping to activate T-lymphocytes, which are crucial for the body's adaptive immune response. Additionally, zinc promotes protein synthesis, which is essential for growth, tissue repair, and the maintenance of muscle mass.

This mineral also contributes to various enzymatic reactions within the body, where around 300 different enzymes require zinc for their proper function. Besides immune health and protein synthesis, zinc further supports wound healing, DNA synthesis, and cell division, highlighting its multifunctional role in human health.

The other options suggest roles that are not primarily associated with zinc. Zinc does not provide energy directly, nor is it involved in carbohydrate absorption. While it has benefits for skin health, particularly in supporting healing and function, its direct role isn't specifically about maintaining skin hydration. Thus, the focus of zinc's benefits centers around immune support and protein utilization in the diet.