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
Which component of St. pyogenes has cross reactivity with synovium of human ? 
Select and explain. 
A. Capsular hyaluronic acid, B. Cell proteins, C. Group A carbohydrate antigens, D. Peptidoglycan
A: Capsular hyaluronic acid
Answer: A: Capsular hyaluronic acid 
Explanation: None