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: Unknown
All these are the properties of exotoxin except: 
Select and explain. 
A. Heat stable, B. Highly antigenic, C. Neutralized by antibodies, D. Protein in nature
A: Heat stable
Answer: A: Heat stable 
Explanation: (Refer: Anantha Narayanan and Paniker’s Textbook of Microbiology, 9th edition, pg no: 75)
Differences between Exotoxin and Endotoxin