Final answer:
The bartender's immediate responsibility before serving a drink is to ensure the customer is of legal drinking age and not visibly intoxicated.
Step-by-step explanation:
Before serving a drink, the bartender has the immediate responsibility to ensure that the person being served is of legal drinking age. This is to comply with the law and avoid serving alcohol to minors. The bartender may ask for identification, such as a driver's license or passport, to verify the customer's age.
Additionally, the bartender should also assess the customer's level of intoxication. If a customer appears to be visibly intoxicated or shows signs of impairment, the bartender should refrain from serving them more alcohol. This is to prevent overconsumption and potential harm to the customer and others.
In both cases, the bartender is responsible for adhering to the laws and regulations regarding the sale and service of alcohol in their jurisdiction.