Which of the following most accurately defines croup?

A) Bacterial infection, affects the lower airway, affects patients younger than 6 months old
B) Bacterial infection, affects the upper airway, affects patients 6 months to 6 years old
C) Viral infection, affects the lower airway, affects patients older than 6 years of age
D) Viral infection, affects the upper airway, affects patients 6 months to 6 years old

Answer: D) Viral infection, affects the upper airway, affects patients 6 months to 6 years old