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 hot-cold phenomenon is seen due to which toxin- 
Select and explain. 
A. Alpha lysin, B. Beta lysin, C. Gamma lysin, D. Theta lysin
B: Beta lysin
Answer: B: Beta lysin 
Explanation: Beta hemolysin: is a sphingomyelinase hemolytic for sheep Blood cells but not for human or rabbit blood cells . It exhibits hot cold phenomenon the hemolysis being at 37degC but becoming evident only after chilling Ref: Ananthanarayan & paniker's Textbook of Microbiology 9th edition pg no 202