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
Trivalent oral polio vaccine contains, type 3 virus: 
Select and explain. 
A. 300,000 TCID 50, B. 200,000 TCID 50, C. 100,000 TCID 50, D. 400,000 TCID 50
A: 300,000 TCID 50
Answer: A: 300,000 TCID 50 
Explanation: None