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': 'Which of the following are the objective tests of refraction ? \nSelect and explain. \nA. Retinoscopy, B. Refractometry, C. Keratometry, D. All the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., All the above", 'role': 'assistant'}]