This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Physiology
A 43-year-old 190 cm man post a flight to Chennai presents with left-sided chest discomfort and dyspnea. On chest X-ray, there is a small area devoid of lung markings in the apex of the left lung. Diagnosis is? 
Select and explain. 
A. Spontaneous pneumothorax, B. Myocardial infarction, C. Acute cor pulmonale, D. Aortic dissection
A: Spontaneous pneumothorax
Answer: A: Spontaneous pneumothorax 
Explanation: Ans. A Spontaneous pneumothoraxRef: CMDT 2019 pg. 325Spontaneous pneumothorax occurs from a rupture of an apical pleural bleb and is associated with tall, young males and is also seen with aeroplane ascent.