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: Social & Preventive Medicine
[{'content': 'Best statistical data diagram to depict incidence change over a period of tissue is \nSelect and explain. \nA. Pie char, B. Histogram, C. Scatter diagram, D. Line diagram', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]