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
Most crucial part of tuberculosis control programme is - 
Select and explain. 
A. Contact tracing, B. BCG vaccination, C. Treatment of sputum positive cases, D. Treatment of X-ray positive cases
C: Treatment of sputum positive cases
Answer: C: Treatment of sputum positive cases 
Explanation: The most powerful weapon in tuberculosis control is → case finding and lit.
Cases are defined by WHO as a patient whose sputum is positive for tubercle bacilli.