Which of the following statements regarding streptococci is INCORRECT?

Which of the following statements regarding streptococci is INCORRECT?
 
  A. The organisms are classified based on the carbohydrate antigens present in their cell walls and on the type of hemolysis produced by the organism growing on a blood agar plate.
  B. Most alpha hemolytic streptococci are very pathogenic.
  C. Group A beta streptococci may cause serious respiratory tract infections such as streptococcal pharyngitis, and such infections may be followed by rheumatic fever.
  D. Group B beta streptococci may colonize the genital tract of pregnant women and may lead to an infection in the infant caused by the streptococcus acquired by the infant during delivery.