Final answer:
Structure/function claims on dietary supplements can legally describe how a nutrient affects normal bodily function, but cannot claim to prevent, treat, cure, or diagnose diseases without a mandatory FDA disclaimer.
Step-by-step explanation:
Regarding the use of structure/function claims on dietary supplements, the valid statement is that they can be used to describe how a nutrient affects normal bodily function. According to regulations set by the Food and Drug Administration (FDA), supplement labels can state that an ingredient may reduce the risk of a disease or target certain body systems, but cannot claim to diagnose, treat, cure, or prevent any disease without a disclaimer. This is because the claims have not been evaluated by the FDA, and supplements with such claims must indicate that the product is not intended "to diagnose, treat, cure, or prevent any disease." Therefore, correct answer out of the provided options is that a dietary supplement can be marketed with statements concerning how a nutrient affects normal bodily function.