This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small & Large Intestine, Subject name: Surgery
[{'content': 'Following is least common about angiodysplasia of colon: \nSelect and explain. \nA. Involvement of cecum, B. Involvement of rectum in 50% of cases, C. Affecting age group >40 years, D. Cause of troublesome lower GI hemorrhage', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) Involvement of rectum in 50% cases* Angiodysplasia is rare in rectum* Causes troublesome intermittent lower GI bleeding. Very difficult to diagnose', 'role': 'assistant'}]