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: Unknown
Pallas sign seen in 
Select and explain. 
A. Sarcoidosis, B. Emphysema, C. Pulmonary embolism, D. Myeloma
C: Pulmonary embolism
Answer: C: Pulmonary embolism 
Explanation: Chest radiograph signs in PE are ,
Pallas sign – enlarged right descending pulmonary artery Hamptons hump- wedge shaped density above diaphragm Westermark sign- focal oligemia.