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
Not a Radiological finding of pericardial effusion 
Select and explain. 
A. Cardiomegaly, B. Oreo cookie sign, C. Water bottle or flask shaped heart, D. Dock's sign
D: Dock's sign
Answer: D: Dock's sign 
Explanation: Dock's sign (inferior notching of 3-8 ribs).
Seen in coarctation of aorta.