<prompt> An 8 years old child is having sore throat with grey-white membrane in throat. Throat swab culture is showing following growth. The causative organism is-Streptococcus pyogenesH. influenzaeCorynebacteriumNone  <response>: Ans. is c i.e., Corynebacterium Grey-white membrane in throat and block colonies on tellurite agar suggest the diagnosis of Diphtheria, caused by Corynebacterium diphtheriae. 