This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Cobblestone appearance of oral mucosa: 
Select and explain. 
A. Crohn disease., B. Ulcerative colitis., C. Whipple disease., D. All of the above.
A: Crohn disease.
Answer: A: Crohn disease. 
Explanation: Crohn disease:

A type of granulomatous disease involving the intestinal mucosa
Also called regional enteritis
Characterized by granulomatous, superficial ulcerations of the intestinal tract with frequent fistulas developing onto body surfaces or viscera, or between intestinal loops.