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: Microbiology
Most common causative organism for lobar pneumonia is - 
Select and explain. 
A. Staphylococcus aureus, B. Streptococcus pyogenes, C. Streptococcus pneumoniae, D. Haemophilus influenzae
C: Streptococcus pneumoniae
Answer: C: Streptococcus pneumoniae 
Explanation: Streptococcus pneumoniae is the Most common causative organism for lobar pneumonia
Adult: MC serotype associated: Type 1-8
Children: Type 6, 14, 19, 23 are frequently associated serotypes
Most Virulent: Type 3.

Ref: Apurba Sastry’s Essentials of Medical Microbiology 1/e p233 , Ananthanarayan 9/e p222