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: Medicine
Cyanosis NOT improving with 100% oxygen in case of- 
Select and explain. 
A. Cardiac asthma, B. Interstitial lung disease, C. Bronchial asthma, D. Tetralogy of Fallot (TOF)
D: Tetralogy of Fallot (TOF)
Answer: D: Tetralogy of Fallot (TOF) 
Explanation: None