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What is All are true about streptococcus except : and explain in detail?
“Mucoid colonies are due to production of capsule of hyaluronic acid not due to M protein.”
Harrison 17/e, p 882
Growth characteristic of Strep. pyogenes :

On blood agar virulent stains forms matt or mucoid colonies while avirulent form glossy colonies.
M, T, R are proteins found on outer part of cell wall and forms the basis of Griffith classification.

– M protein - Acts as virulence factor and antibody against it are protective.
– T and R protein - No relation to virulence

Streptococci (Except enterococci) are usually susceptible to penicillin so option “d” is not completely wrong. As option “a” is completely wrong, that would be the answer.