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: Pediatrics
Croup syndrome is usually caused by –a)  Rhinovirusesb)  Coxsackie A virusc) Coxsackie B virusd) Para influenza 
Select and explain. 
A. b, B. c, C. ac, D. ad
D: ad
Answer: D: ad 
Explanation: Croup (Laryngotracheobronchitis)

Croup is a viral infection of the upper respiratory tract.
Children between the age of 1-5 years are affected.

Causative organisms → Parainfluenza type I, RSV, Influenza, Adenovirus, Rhinovirus