This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory infections, Subject name: Pediatrics
Most common bacteria responsible for the following condition seen in a child who presents with high grade fever and sore throat is? 
Select and explain. 
A. Group A streptococcus, B. Group B streptococcus, C. Corynebacterium diphtheria, D. Staphylococcus aureus
A: Group A streptococcus
Answer: A: Group A streptococcus 
Explanation: Enlarged & congested tonsils with palatal petechiae- suggestive of acute pharyngotonsillitis due to Streptococcus pyogenes :group A beta hemolytic streptococcal infection