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
Prevalance of tuberculosis infection is determined by- 
Select and explain. 
A. Sputum examination, B. Mantoux, C. Clinical examination, D. MMR
B: Mantoux
Answer: B: Mantoux 
Explanation: None