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: Dental
Which of the following is an important constituent of gram-negative microorganisms that contributes to initiation of the host inflammatory response? 
Select and explain. 
A. Exotoxin, B. Lipoteichoic acid, C. Endotoxin, D. Peptidoglycan
C: Endotoxin
Answer: C: Endotoxin 
Explanation: Endotoxin or lipopolysaccharide is an important constituent of the gram-negative outer membrane that contributes to initiation of the host inflammatory response.