Bile solubility is used
Ans. is 'c' i.e., Differentiation of pneumococci from streptococci . Pneumococcus is bile soluble, while streptococcus is insoluble.
Differentiation of staphylococcus from streptococcus
Differentiation of group B streptococci from other streptococci
Differentiation of pneumococci from streptococci
Differentiation of streptococci from neisseria