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': 'Lens has a respiratory quotient of: \nSelect and explain. \nA. 1, B. 0.6, C. 0.7, D. 0.9', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. 1', 'role': 'assistant'}]