If a person has been drinking alcohol, what can effectively sober them up?

The correct answer is time. When a person consumes alcohol, their body metabolizes it at a constant rate, which cannot be accelerated by any external factors, including coffee, showers, or exercise. The liver processes alcohol, and this takes time—typically about one hour to metabolize one standard drink. Regardless of how a person feels after trying to consume substances or engage in activities, the alcohol remains in their bloodstream until it is fully metabolized. Therefore, waiting is the only effective way to sober up and reduce blood alcohol concentration.