This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'Daisy head colonies are seen with \nSelect and explain. \nA. Staphylococcus aureus, B. Corynebacterium diphtheriae, C. Staphylococcus pyogenes, D. Anthrax', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A round grey or black colony with a narrow translucent scalloped border, typically produced by Corynebacterium diphtheriae on tellurite blood agar. Tellurite inhibits the growth of most other bacteria, acting as a selective agent. Diphtheria bacilli reduce tellurite to metallic tellurium, which is incorporated in the colonies giving them a grey or black colour. Reference: Textbook of Microbiology; Anathanarayan and panicker&;s; 9th edition; Page no: 237', 'role': 'assistant'}]