This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
Westermark's sign, Hampton's hump, Palla's sign are all features of which condition on chest X-ray 
Select and explain. 
A. Tubercular pleural effusion, B. Pulmonary Embolism, C. Acute Pulmonary adema, D. Left ventricular failure
B: Pulmonary Embolism
Answer: B: Pulmonary Embolism 
Explanation: A normal or nearly normal chest x-ray often occurs in PE. Well-established abnormalities include focal oligemia (Westermark's sign), a peripheral wedged-shaped density above the diaphragm (Hampton's hump), and an enlarged right descending pulmonary aery (Palla's sign).Harrison 19e pg: 1633