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
Under passive surveillance for tuberculosis, indication for sputum microscopy cough is for weeks or more 
Select and explain. 
A. 8 weeks, B. 4 weeks, C. 6 weeks, D. 3 weeks
D: 3 weeks
Answer: D: 3 weeks 
Explanation: None