Answer is 14 grams (1/2 ounce) of pure alcohol.
Reason: In the United States, one "standard" drink contains about 14 grams of pure alcohol, ( about 1/2 ounce) which is found in: 12 ounces of regular beer, which is usually about 5% alcohol. 4 ounces of wine, which is typically about 12% alcohol. 1 ounce of distilled spirits, which is about 40% alcohol.