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
Ellis curve is seen in 
Select and explain. 
A. Pheumothorax, B. Pheumonia, C. Asthma, D. Pleural effusion
D: Pleural effusion
Answer: D: Pleural effusion 
Explanation: o On chest X-rays, pleural effusion presents as homogenous opacity.
o Typically this opacity has a fairly well defined concave upper edge, is higher laterally than medially and obscures the diaphragmatic shadow