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': 'Tuberculin test denotes \nSelect and explain. \nA. Previous or present sensitivity to tubercle proteins, B. Patient is restant to tuberculosis, C. Person is susceptible to tuberculosis, D. Protective immune status of individual againts tuberculosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A positive reaction to the tuberculin test is generally accepted as evidence of past or present infection of M.tuberculosis . Ref: PARK&;S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 23rd edition , Page :185', 'role': 'assistant'}]