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: Pediatrics
A 10-month-old child presents with an abnormal inspiratory sound; mother complaints that the sound increases with cry, and decreases when the child sleeps in prone position. What would be the probable diagnosis? 
Select and explain. 
A. Croup, B. Acute epiglottitis, C. Laryngitis, D. Laryngomalacia
D: Laryngomalacia
Answer: D: Laryngomalacia 
Explanation: d. Laryngomalacia(Ref: Nelson's 20/e p 2036)Clinical Features of Laryngomalacia:Stridor is inspiratory, low pitched & exacerbated by crying, agitation, or feedingResults from the collapse of supraglottic structures inwards during inspirationSymptoms appear within first 2 weeks of life increase in severity for up to 6 monthsStridor improves when the baby sleeps in prone position.