What does a standard drink of 1.5 fluid ounces of 80 proof liquor contain?

A standard drink in the context of alcohol consumption is defined as a beverage that contains a specific amount of pure alcohol. For distilled spirits, this amount is generally 0.6 fluid ounces of pure ethyl alcohol.

In the case of 80 proof liquor, which is 40% alcohol by volume (ABV), a standard serving size of 1.5 fluid ounces would indeed yield approximately 0.6 fluid ounces of ethyl alcohol. This is calculated by taking the total volume of the liquor (1.5 ounces) and multiplying it by the ABV (0.40), resulting in 0.6 fluid ounces of pure ethanol.

This understanding is pivotal for various applications including calculating blood alcohol content, providing guidelines for responsible drinking, and determining legal limits for operating a vehicle. The other choices incorrectly reflect the alcohol content based on the standard definitions and calculations for a standard drink.