Final answer:
The correct answer is (a) observable symptoms, which are noticeable behaviors that indicate how individuals are affected by alcohol. These symptoms are important for hosts to monitor for the safety of their guests.
Step-by-step explanation:
Your guests' behavior provides observable symptoms that show you how they are being affected by alcohol. Observable symptoms are feelings or experiences reported by a person that can indicate a reaction or condition. In the case of alcohol consumption, these could include slurred speech, loss of coordination, mood swings, or changes in behavior. Unlike medical diagnostic tests, these symptoms are directly noticeable without requiring the individual's input or self-assessment.
Observable symptoms as a response to alcohol intake are critical for hosts to monitor to ensure the safety and well-being of their guests. Being aware of these symptoms enables a host to decide whether a guest may need medical attention or should be discouraged from consuming more alcohol.