Answer:
Toxins produced by the microbe.
Step-by-step explanation:
Pasteurization is a method used to kill the microbes by high temperature.Specific antimicrobial drugs are used to kill the microbes if the microbe is pathogen in nature.
The death rate of microbes depend on the type of microbes, its characteristics and the time to which it has been exposed. The toxins produced by the microbes will affect its rate of infection but doesnot have any effect on the death rate.
Thus, the correct answer is option (d).