Final answer:
The temperature range of 41°F to 135°F (5°C to 57°C) is where pathogens grow the fastest, being the preferred range for mesophilic organisms such as many human pathogens.
Step-by-step explanation:
The temperature range that promotes the fastest growth of pathogens is b. 41°F to 135°F (5°C to 57°C). This range is suitable for mesophilic organisms, which include many common pathogens that are adapted to live in temperatures similar to the human body temperature (37°C or 98.6°F). Pathogens thrive in this zone because it's close to conditions within the human body and because it provides the optimum temperature for the metabolic processes necessary for their rapid multiplication.
Sub-optimal temperatures, whether colder or hotter than this range, tend to inhibit the growth of microorganisms. Refrigeration and freezing slow down microbial metabolism significantly, while temperatures above this range, especially pasteurization temperatures above 60°C (140°F), typically kill bacteria or stop their growth because of protein denaturation, membrane disruption, and other cellular damages.