This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Microbiology
[{'content': 'Z-value of an organism: \nSelect and explain. \nA. The time required to kill 90% of cells at a particular temperature, B. The time required to kill all cells at a particular temperature, C. Is the temperature change required for the D-value to change by a factor of ten, D. Is the temperature change required for the D-value to change by a factor of five', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C. Is the temperature change required for the D-value to change by a factor of tena. D value of an organism is the time needed at a certain temperature to kill 90% of the organisms in the medium,b. Z-value of an organism is the temperature change required for the D-value to change by a factor of ten', 'role': 'assistant'}]