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: Ophthalmology
[{'content': 'Radius of curvature of the anterior surface of an adult crystalline lens with accommodation at rest is: \nSelect and explain. \nA. 7 mm, B. 10 mm, C. 8 mm, D. 9 mm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. 10 mm', 'role': 'assistant'}]