Which of the following definitions best describes gastritis?
Correct Answer: C
Rationale: The correct answer is C: 'Inflammation of the gastric mucosa.' Gastritis is characterized by inflammation of the stomach lining, specifically the gastric mucosa. This inflammation can be caused by various factors such as infections, medications, alcohol, or autoimmune diseases. Choice A, 'Erosion of the gastric mucosa,' is incorrect because erosion refers to the wearing away of tissue rather than inflammation. Choice B, 'Inflammation of a diverticulum,' is incorrect because gastritis specifically involves inflammation of the stomach lining, not a diverticulum. Choice D, 'Reflux of stomach acid into the esophagus,' describes gastroesophageal reflux disease (GERD), which is different from gastritis.