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': 'Non-motile organism: \nSelect and explain. \nA. E. coli, B. Vibrio cholera, C. Protein in nature, D. Antigenic', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. d. Antigenic', 'role': 'assistant'}]