This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
[{'content': 'The wavelength of laser {in nanometers} for shaping cornea in refractive surgery is - \nSelect and explain. \nA. 193 nm, B. 451 nm, C. 532 nm, D. 1064 nm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Excimer laser is used : wavelength 193nm Mechanism : photo ablation. Uses : PRK, PTK, LASIK', 'role': 'assistant'}]