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
Commonest organism causing acute epiglotitis is 
Select and explain. 
A. H. influenza, B. Clostridium, C. S. pneumonia, D. RSV
A: H. influenza
Answer: A: H. influenza 
Explanation: None