This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology Pa 1 (Gram Positive Cocci, Gram Negative Cocci), Subject name: Microbiology
Which of the following streptococcal antigen cross reacts with synol fluid? 
Select and explain. 
A. Carbohydrate (group A), B. Cell wall protein, C. Capsular hyaluronic acid, D. Peptidoglycan
C: Capsular hyaluronic acid
Answer: C: Capsular hyaluronic acid 
Explanation: Antigens cross reactivity between Streptococcus antigens and the corresponding human antigen Streptococcal component Human tissue Capsular hyaluronic acid Synol fluid Cell wall protein Myocardium Group A carbohydrate Cardiac valves Cytoplasmic membrane antigen Vascular intima Peptidoglycans Skin antigens