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
Rib notching is found in – a) Neurofibromatosisb) Lymphangiomyomatosisc) Aortic aneurysmd) Taussig-Bing operatione) Aortic obstruction 
Select and explain. 
A. acd, B. ade, C. abd, D. ad
B: ade
Answer: B: ade 
Explanation: Neurofibromatosis and aortic obstruction (thrombosis) may cause rib notching.
Taussig - bing malformation, when associated with coarctation of aorta, can cause rib notching.