Final answer:
The most practical way to guard against allergic reactions in restaurant guests is to provide complete information about the ingredients in the menu selections. Hence, the last option is correct.
Step-by-step explanation:
The most practical way to guard against allergic reactions in restaurant guests is to provide complete information about the ingredients in the menu selections, and, upon request, reveal ingredients that contain allergens.
By providing complete and accurate information about the ingredients in the menu selections, restaurant guests can make informed decisions about their food choices and avoid potential allergens. This allows individuals with food allergies to enjoy a safe dining experience and helps to prevent allergic reactions.
For example, if a restaurant guest has a peanut allergy, they can ask for information about dishes that contain peanuts and avoid ordering those items to prevent an allergic reaction.