Final answer:
Enteritis refers to the inflammation of the small intestine.
Step-by-step explanation:
The correct answer is A. Small Intestine. Enteritis refers to the inflammation of the small intestine. It is often caused by infections, such as due to bacteria or viruses, and can lead to symptoms like diarrhea, abdominal pain, and vomiting. The small intestine is responsible for the further digestion and absorption of nutrients from food.