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
Aplastic anemia in hereditary spherocytosis precipitated by- 
Select and explain. 
A. Parvo virus, B. HIV, C. Adenovirus, D. Influenza virus
A: Parvo virus
Answer: A: Parvo virus 
Explanation: Answer is A (Parvovirus) Aplastic crisis is usually triggered by an acute parvovirus infection.