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: ENT
A 2-year-old boy presenting with sudden severe dyspnea, most common cause is: 
Select and explain. 
A. Foreign body, B. Bronchiolitis, C. Asthmatic attack, D. None
A: Foreign body
Answer: A: Foreign body 
Explanation: In case of stridor with acute airway obstruction (i.e. dyspnea) always history of any foreign body ingestion should be taken.