Smooth (S)and rough (R)strains of Streptococcus pneumonia are distinct because of their ability to cause illness (death in rodents).This trait is controlled by genes that regulate:

A)the production of a protective polysaccharide coat (capsule)around each cell.
B)the production of lethal toxins.
C)the speed of bacterial growth.
D)the metabolic rate of microbial glycolysis.
E)the bacterial ability to penetrate through the membrane of animal cells.