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': 'Net power of Cornea \nSelect and explain. \nA. +48D, B. +43D, C. +45D, D. +60D', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Power of anterior surface of Cornea = +48D\nPower of posterior surface of Cornea= –5D\nNet power of Cornea= +48D –5D = +43D', 'role': 'assistant'}]