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
Which of the following is not a killed vaccine ? 
Select and explain. 
A. Polio, B. HBV, C. HAV, D. Yellow fever vaccine
D: Yellow fever vaccine
Answer: D: Yellow fever vaccine 
Explanation: Ans. is 'd' i.e., Yellow fever vaccine Yellow fever vaccine is a killed vaccine.