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
Yellow fever vaccination starts protection after how many days of injection - 
Select and explain. 
A. 5 days, B. 10 days, C. 15 days, D. 20 days
B: 10 days
Answer: B: 10 days 
Explanation: None