Which option correctly represents one standard drink for spirits (40% ABV)?

• A. 30 ml
• B. 100 ml
• C. 60 ml
• D. 150 ml

Answer: (A)

One standard drink is defined as a fixed amount of pure ethanol. For most guidelines, that equals about 10 grams of ethanol. Spirits at 40% ABV contain ethanol at 40% of the liquid’s volume. If you take about 30 mL of such a spirit, you’re getting roughly 12 mL of ethanol, which is around 9–10 grams of ethanol when you convert volume to mass. That matches the definition of one standard drink. If you used more liquid, like 60, 100, or 150 mL, you’d be consuming far more ethanol (roughly double, triple, or more), so those amounts aren’t standard drinks for spirits. So the amount that represents one standard drink for spirits with 40% ABV is about 30 mL.