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': 'All the following strains of proteus are used in Weil-Felix reaction Except \nSelect and explain. \nA. OX 2, B. OX 19, C. OX K, D. OX O', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Alkali stable polysaccharide, a surface antigen is seen in some rickettsiae and some strains of Proteus bacilli. This is the basis for the Weil-Felix reaction used for the diagnosis of rickettsial infections by the demonstration of agglutinins to Proteus strains OX 19, OX 2, and OX K.Ref: Ananthanarayan; 7th edition; Page no: 413', 'role': 'assistant'}]