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': 'Endotoxin consists of _____. \nSelect and explain. \nA. Lipopolysaccharide, B. M protein, C. Hyaluronidase, D. Lactic acid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Endotoxin or lipopolysaccharide is found in the cell walls of gram-negative bacteria.', 'role': 'assistant'}]