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': 'In retinoscopy for refractive error at 1m, we add 1D ; if done at a distance of 66 cm, the additional factor will be – \nSelect and explain. \nA. –2, B. –1.5, C. –0.5, D. –5', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Deduction of 1D for lm and 1.5D when retinoscopy is performed at 2/3rd m (67 cm) distance.', 'role': 'assistant'}]