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
Most common cause of viral pneumonia in infant is- 
Select and explain. 
A. Influenza virus, B. Adenovirus, C. Rhinovirus, D. Parainfluenza virus
A: Influenza virus
Answer: A: Influenza virus 
Explanation: Ans. is 'a' i.e., Influenza virus * The peak attack for viral pneumonia is between the age of 2nd and 3rd years and decrease thereafter.* Viruses causing pneumonia are -# RSV - Most common# Influenza - 2nd most common# Adenovirus# Parainfluenza virus# Rhinovirus * Most common bacterial cause of pediatric pneumonia is streptococus pneumoniae (pneumococcus). Bacteria causing atypical pneumonia commonly are mycoplasma and chlamydia.