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: Physiology
Cyanosis does not occur in severe anemia because: 
Select and explain. 
A. Hypoxia stimulates erythropoietin production, B. Oxygen carrying capacity of available Hb is increased, C. Critica concentration of Hb required to produce cyanosis is reduced, D. Oxygen Hemoglobin curve shift to the right
C: Critica concentration of Hb required to produce cyanosis is reduced
Answer: C: Critica concentration of Hb required to produce cyanosis is reduced 
Explanation: C i.e. Critica concentration of H required to produce cyanosis is reduced