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 virus most commonly causing aplastic crisis in hemolytic anemia is - 
Select and explain. 
A. HIV, B. Herpes virus, C. Parvo virus, D. HTLV
C: Parvo virus
Answer: C: Parvo virus 
Explanation: None