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
A boy with skin ulcer on leg, culture reveals beta hemolysis. Cultures from school children with sore throat some days back also revealed beta hemolysis. What is the similarity between both- 
Select and explain. 
A. Mec A gene is related to it, B. M protein is same, C. C carbohydrate antigen is same, D. Strains causing both are same
C: C carbohydrate antigen is same
Answer: C: C carbohydrate antigen is same 
Explanation: None