This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': 'Fuctional GI disorders can be differentiated from organic GI disorders by \nSelect and explain. \nA. Abdominal pain, B. Diarrhea, C. Tenesmus, D. Bleeding PR', 'role': 'user'}, {'content': "Answer: D \nExplanation: Common causes of Bleeding per rectum hemorrhoids anal fissures (tears in the rectal tissue), diveicula (diveiculitis, including Meckel's diveiculum), infections (bacterial and other pathogens) inflammatory bowel diseases (Crohn's disease and ulcerative colitis), angiodysplasia (fragile blood vessels), tumors,polyps, and bowel trauma. Less common causes include upper GI tract problems like ulcers and Mallory-Weiss tears in the esophagus or a dilated vein or varix. Ref:", 'role': 'assistant'}]