Among the options, Vitamin A is the correct answer as it is a common feed additive that enhances the nutritional value of animal feed. Corn is a feed ingredient, not an additive, while potassium is a mineral rather than a traditional additive. Medicine can be used therapeutically but isn't considered a typical feed additive. ;
The correct answer is D: Vitamin A, as it is a well-known feed additive that enhances the nutritional value of animal feed. Corn is a primary feed ingredient, potassium is a mineral, and medicine is more therapeutic than nutritional, making Vitamin A the most appropriate choice. Feed additives are substances incorporated into animal feed to support their overall health and nutritional needs.
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