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
Endotoxin consists of _____. 
Select and explain. 
A. Lipopolysaccharide, B. M protein, C. Hyaluronidase, D. Lactic acid
A: Lipopolysaccharide
Answer: A: Lipopolysaccharide 
Explanation: Endotoxin or lipopolysaccharide is found in the cell walls of gram-negative bacteria.