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: Microbiology
Which of these need both V and X factors? 
Select and explain. 
A. Hemophilus influenzae, B. H. ducrei, C. H. paraphrophilus, D. All
A: Hemophilus influenzae
Answer: A: Hemophilus influenzae 
Explanation: Ans. is 'a' i.e., Hemophilus influenzae Haemophilus The genus Haemophilus contain small, nonmotile, nonsporing, oxidase positive gram negative bacilli. They are characterized by their requirement of one or both of two accessory growth factors (X and V) present in blood. That's why they are called haemophilus which means blood loving. Different species have different requirement :- H. influenzae, H. aegyptius, H. haemolyticus --0- Factor X & V. H. Parainfluenzae, H. Parahemolyticus, H. Paraphrophilus --p. Factor V. H. ducreyi, H. aphrophilus ---0- Factor X.