<prompt> Corynebacterium diphtheria produce black or grey colonies on the following agarMac-conkey agarPotassium tellurite agarThayer main mediumTinsdale agar  <response>: Corynebacterium produce black or grey colonies on potassium tellurite blood agar It acts as a selective medium for its growth Ref: Textbook of Microbiology Baveja 5th ed Pg 211 