Final answer:
Utensils and food-contact surfaces must come into contact with hot water or a chemical sanitizer for a certain period to be effectively sanitized, which is typically around 30 seconds or more, depending on local health regulations.
Step-by-step explanation:
Utensils and food-contact surfaces must have a sufficient contact time with a sanitizing agent to ensure proper sanitation. For hot water sanitizing, the minimum required contact time is often set by local health codes but can typically be 30 seconds or more at a certain temperature. For chemical sanitizers, such as a chlorine bleach solution, contact times may vary depending on the concentration of the solution and the type of sanitizer used but follows similar principles. It is important to adhere to these times to ensure the safety of the utensils and surfaces that come into contact with food. In your question, since none of the options is exactly 30 seconds, the closest correct option would be (b) 45 seconds.