Final answer:
Food establishments that serve alcoholic beverages must display their liquor license. Nutritional information is required on packaged foods, and while warning signs or drink coupons may be present, they are not required by law.
Step-by-step explanation:
Foods establishments which serve alcoholic beverages are required to display the establishment's liquor license. This is the document that is mandated by law for an establishment to legally sell alcoholic beverages. It's important to note that while nutritional information must be provided on packaged food items according to federal law, this does not typically extend to food served in restaurants unless added nutrients are claimed, and warning signs about the dangers of alcohol consumption or coupons for discounted drinks may be seen in some establishments, but are not universally required.