This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, Subject name: Microbiology
The scientist below contributed to all of the following except 
Select and explain. 
A. Chicken Cholera vaccine, B. Rabies vaccine, C. Diphtheria toxoid, D. Anthrax vaccine
C: Diphtheria toxoid
Answer: C: Diphtheria toxoid 
Explanation: Lois Pasteur (1822-95):*He introduced techniques of sterilization and developed the steam sterilization, hot air oven, and autoclave*He worked on Chicken cholera vaccine, rabies vaccine, and Anthrax vaccine.Diphtheria toxoid work was done by Roux and Yersin.Ref: Ananthanarayan 9th edition, p13