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: Radiology
False about Coarctation of Aorta 
Select and explain. 
A. Double bulge sign is seen, B. Double aortic knuckle, C. Rib notching is seen in 1-8 ribs, D. Rib notching increases with age
C: Rib notching is seen in 1-8 ribs
Answer: C: Rib notching is seen in 1-8 ribs 
Explanation: Rib notching is absent in 1st and 2nd ribs because first and second intercostal arteries do not take part in Collateral Circulation.