This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Anatomy
Cause of central cyanosis include all the following except 
Select and explain. 
A. Chronic asthma, B. Congestive pulmonary stenosis, C. Congestive hea failure, D. Alveolar hypotension
C: Congestive hea failure
Answer: C: Congestive hea failure 
Explanation: CHF is a cause for peripheral cyanosis and not central cyanosis. Cyanosis when present in asthma,pulmonic stenosis and alveolar hypoventilation is of central type. Ref Harrison 19th edition pg 249