This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
Which one of the following factors released by heating a suspension of sheep erythrocytes is required for the growth of Haemophilus Influenzae in chocolate agar? 
Select and explain. 
A. Hemin, B. Nicotinamide adenine dinucleotide (NAD), C. Hemoglobin, D. Hemolysin
B: Nicotinamide adenine dinucleotide (NAD)
Answer: B: Nicotinamide adenine dinucleotide (NAD) 
Explanation: Ans. B. NAD.a. Members of Hemophilus require for one or more of the accessory factors: X & V in bloodb. Factor X is heme whereas factor V is NAD/NADP.c. The V factor (NAD) is trapped in the RBC's in blood agar. Hence, on blood agar, Hemophilus influenzae shows poor growth.d. By heating blood agar, V factor is released into the medium.