This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'Category II treatment - \nSelect and explain. \nA. 2HRZES, B. 1 HRZE, C. 5 HRE, D. All', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Previously treated or category 2 includes combination of all the above drugs', 'role': 'assistant'}]