This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cyanotic Congenital Heart Disease, Subject name: Pediatrics
Differentia] cyanosis occurs in which disease - 
Select and explain. 
A. Severe coarctation, B. Inturrupted aortic arch, C. PPHN, D. All of above
D: All of above
Answer: D: All of above 
Explanation: Ans. is 'd' i.e., All of above Differential cyanosis -o With normally related great arteries, oxygen saturation may be higher in the upper than lower extremity' in patients if there is right-to-left shunting through the ductus arteriosus.# Seen with severe coarctation or interrupted aortic arch.#. May also occur in patients persistent pulmonaiy hypertension of the newborn.o The differential effect is reduced if there is also right-to-left shunting at the level of the foramen ovale, or if there is left-to-right shunting across coexisting ventricular septal defect