The correct term from the provided options that describes the time required to kill 90% of the microbes within a sample at a given temperature is the D-value.
The term you are asking about, which compares our tolerance to a substance with the amount needed to kill bacteria, doesn't match with the options provided (A, B, C, or D). It seems like there might be a mix-up in the question. However, in toxicology and pharmacology, the concept you're describing is somewhat related to the therapeutic index, which measures the safety of a drug by comparing the therapeutically effective dose to the lethal dose in 50% of the population (LD50). Nonetheless, the correct answer from the provided reference information is the D-value, which is used to describe the time required to kill 90% of the microbes within a sample at a given temperature.