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
Chest X-ray of an industrial worker exposed to asbestos over 20 years shows an ill-defined rounded opacity in the lower lobe with a 'comet tail' appearance on PA view. Which of the following is the most likely diagnosis- 
Select and explain. 
A. Mesothelioma, B. Bronchogenic carcinoma, C. Round Atelectasis, D. Pulmonary infarct
C: Round Atelectasis
Answer: C: Round Atelectasis 
Explanation: A rounded opacity in the lower lobe of an industrial worker exposed to Asbestos with a classical 'comet tail' sign suggests a diagnosis of 'Rounded Atelectasis'.
Comet Tail Sign

This refers to the presence of crowded bronchi and blood vessels that extend from the lower border of the mass and coverage to the adjacent hilum creating a whorled appearance of the bronchovascular bundle.