This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Safety pin appearance is shown by-a) Hemophilus ducreyib) Chlamydiac)  Donovani granulomatisd) Mycoplasma \nSelect and explain. \nA. a, B. ac, C. ad, D. b', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Bipolar staining (safety pin appearance) \n\nSome bacteria display a safety pin appearance due to the accumulation of dye at the poles of the cells.\n\n\nThis characteristic is called bipolar staining.\n\n\nBacteria showing bipolar staining are-\n\n\nCalymmatobacter granulomatis (Donovani granulomatis)\nPseudomonas mallei\nPseudomonas pseudomallei\xa0 \xa0\nVibrio parahemolyticus\nYersinia pestis\nH.ducreyi', 'role': 'assistant'}]