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': 'Screening of retina in Non - insulin dependent diabetes mellitus starts after \nSelect and explain. \nA. Start after 5 years, B. Start after 6 years, C. Start immediately, D. Start after 3 months', 'role': 'user'}, {'content': 'Answer: C \nExplanation: NIDDM - start immediately.\nIDDM - start within 5 years.', 'role': 'assistant'}]