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: Anatomy
[{'content': "Which of the following statements about 'Valves of Houston' is true - \nSelect and explain. \nA. The middle valve corresponds to the middle convex fold to the Right, B. The upper valve corresponds to peritoneal reflections, C. The valves contain all three layers of muscle wall, D. Valves disappear after mobilization of Rectum.", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Valves of Houston are lost after full mobilization of the Rectum.\nThe middle valve is located on the Right Wall but corresponds to the middle convex fold to the left.\nThe middle valve (and not upper valve) corresponds to the level of peritoneal reflection.\nValves of Houston do not contain all three layers of the muscle wall.', 'role': 'assistant'}]