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
Exotoxins are: 
Select and explain. 
A. Lipid-polysaccharide complex, B. Protein compound, C. Lipoprotein, D. None
B: Protein compound
Answer: B: Protein compound 
Explanation: None