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
Lancefield classifiction of Streptococcus is based on 
Select and explain. 
A. M protein, B. Carbohydrate C antigen of cell wall, C. Hemolysis, D. Bile solubility
B: Carbohydrate C antigen of cell wall
Answer: B: Carbohydrate C antigen of cell wall 
Explanation: Based on oxygen requirement - aerobic/ ananerobic Brown's classification -Based on haemolysis on blood agar (alpha, beta, gamma) Streptococci maybe classified based on carbohydrate C antigen of cell wall into Lancefield groups (A-W ecxcluding I, J) M protein types classified into Griffith types