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: Medicine
The vaccine currently used against hepatitis B infection is 
Select and explain. 
A. Killed pooled serum, B. Live attenuated, C. Recombinant, D. Synthetic vaccine
C: Recombinant
Answer: C: Recombinant 
Explanation: None