A 37-year-old man has had nausea and vomiting for 5 weeks. He experienced an episode of hematemesis yesterday. On physical examination he has no abnormal findings. Upper GI endoscopy is performed, and there is a 1.5 cm diameter lesion in the gastric antrum which appears to be an area with loss of the epithelial surface. These findings are most typical for which of the following pathologic processes? A. Abscess
B. Serositis
C. Granuloma
D. Gangrene
E. Ulcer