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 is the least common corneal dystrophy \nSelect and explain. \nA. Macular Dystrophy, B. Lattice type I, C. Lattice type III, D. Granular Corneal Dystrophy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Macular Dystrophy', 'role': 'assistant'}]