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
Strain used for BCG vaccine - 
Select and explain. 
A. Edmonston Zagreb strain, B. Oka strain, C. 'Danish' 1331, D. RA 27/3strain
C: 'Danish' 1331
Answer: C: 'Danish' 1331 
Explanation: Ans. is 'c' i.e., Danish 1331