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: Unknown
[{'content': 'Which of the following does not develop from mesoderm: \nSelect and explain. \nA. Muscles of bladder, B. Iris muscle, C. Deltoid muscle, D. LPS', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The musculature of the iris is of ectodermal origin, but the ciliary muscle is of mesodermal origin.', 'role': 'assistant'}]