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 ARV has been recommended by WHO as the most effective - 
Select and explain. 
A. Duck cell vaccine, B. Chick fibroblast vaccine, C. HDCV, D. Sheep brain vaccine
B: Chick fibroblast vaccine
Answer: B: Chick fibroblast vaccine 
Explanation: None