Carrom coin appearance of pneumococcus is due to: (A) Capsular polysaccharide, (B) C- Carbohydrate antigen, (C) Pneumolysin, (D) Autolysin
Answer is D. Autolysin is amidase enzyme that cleaves peptidoglycan leading to autolysis of cells. 
This property is responsible for carrom coin appearance of pneumococcal colonies.