This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
Among the toxin produced by Clostridium botulinum, the non-neurotoxic one is 
Select and explain. 
A. A, B. B, C. C1, D. C2
D: C2
Answer: D: C2 
Explanation: Eight types of C.botulinum have been identified (A, B, C1, C2, D, E, F and G) based on the immunological difference in the toxins produced by them. The toxin produced by different strains of Clostridium botulinum are identical in their pharmacological activity but are neutralized only by homologous antiserum. An exception is a C2 toxin which shows enterotoxic activity while others are neurotoxins. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 269