This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
H.parainfluenzae requires which of the following factors 
Select and explain. 
A. Only Factor X, B. Only Factor V, C. Both factor X and V, D. None of the above
A: Only Factor X
Answer: A: Only Factor X 
Explanation: H.influenzae, H.haemolyticus, and H.aegyptius: requires both factor X and VH.parainfluenzae, H.parahaemolyticus, and H.paraphrophilus: Requires only factor VH.aphrophilus: Doesn't require both factors(Ref: Ananthanarayan 9th edition, p328)