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': 'What is the power of a lens if the focal length is 0.75m? \nSelect and explain. \nA. 1 D, B. 1.3 D, C. 2 D, D. 2.3 D', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Power = 1/Focal length\n= 1/0.75\n= 4/3\n= 1.3D', 'role': 'assistant'}]