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
The commonest cause of Bacterial Pneumonia in children is – 
Select and explain. 
A. Streptococcus pyogenes, B. Hemophilus influenzae, C. Streptococcus pneumoniae, D. Staphylococcus aureus
C: Streptococcus pneumoniae
Answer: C: Streptococcus pneumoniae 
Explanation: Pneumonia 

Pneumonia is an inflammation of the parenchyma of lungs.
Most of the infective pneumonia is caused by bacteria and viruses.

Bacterial causes

Streptococcus pneumoniae (pneumococci) is the most common bacterial pathogens followed by chlamydia pneumonia and mycoplasma pneumonia. — Nelson 18th /e 1795
So, the three most common bacterial causes are → Pneumococci, Mycoplasma pneumoniae, Chlamydia pneumonia
Other bacteria → Streptococcus pyogenes, Staphylococcus aureus, H. influenzae