This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small and Large intestine, Subject name: Anatomy
[{'content': "All the following are false about houston's valve except: \nSelect and explain. \nA. They disappear on distension, B. They contain all layers of muscle layer, C. Placed transversely, D. Middle valve is the most constant and fold towards right side", 'role': 'user'}, {'content': "Answer: C \nExplanation: The transverse folds of rectum (or Houston's valves) are semi-lunar transverse folds of the rectal wall that protrude into the rectum, not the anal canal as that lies below the rectum. CHOICE EXPLANATION & ELIMINATION REASON 1 False statement. Prominent on distension 2 False statement. Contains only circular muscles 3 True statement.Placed transversely 4 False statement. Middle valve constant and fold towards left side", 'role': 'assistant'}]