Lancefield classification is based on which of the following cellular structure?

Lancefield classification is a serological classification of beta hemolytic streptococci. This classification is based upon the detection on group specific carbohydrate antigen on the cell wall of streptococci. Beta hemolytic streptococci are classified into 21 serologic groups known as Lancefield groups designated from A to V. Griffith typing: Based on the presence of M, T, and R protein antigens present on the cell surface, Streptococcus pyogenes are classified into 80 serotypes. M protein is the most impoant type specific antigen. Ref: Textbook Of Microbiology And Immunology By Parija, page 191-2.