The "String of pearl" colonies on Nutrient agar is produced by -

Ans. is 'c' i.e., Bacillus String of pearl reactiono String of pearl reaction is used to differentiate B. anthracis from B. cereus and other aerobic spore forming bacteria,o When B. antharcis is grown on a solid medium containing penicillin, the cells become larger, spherical and occur in chains on the surface of the agar, resembling a string of pearls.Important characteristic feature of B. Anthraciso Gram positiveo Non-motile fall other members of genus Bacillus are motile)o Polypeptide capsuleo "Frosted glass appearance " of cultureo "Invertedfor tree appearance " of cultureo Medusa head colonieso String of pearl's reactiono "Cut glass appearance"o MTadyean's reactiono Selective media - PLET medium