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': 'Endotoxins have all but one of the properties given below: \nSelect and explain. \nA. Produced by gram negative bacteria, B. Produced by gram positive bacteria, C. Not secreted outside the cell, D. Cannot be toxoided', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]