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: Microbiology
[{'content': 'Light microscopy resolution -( \nSelect and explain. \nA. 200 nm, B. 20 nm, C. 0.2 nm, D. 300 nm', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., 300 nm", 'role': 'assistant'}]