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': 'Tuberculin positivity means: \nSelect and explain. \nA. Immunodeficiency, B. Resistance to tubercular protein, C. Infection with mycobacterium, D. Patient suffering from disease', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Infection with mycobacterium', 'role': 'assistant'}]