which factor is the only way to lower bac?

The only way to lower Blood Alcohol Concentration (BAC) is to allow time for the body to metabolize and eliminate the alcohol. There is no method, such as drinking coffee, taking cold showers, or eating food after drinking, that can speed up this process. The liver processes alcohol at a steady rate, typically about one standard drink per hour, and BAC will decrease only as the body metabolizes the alcohol over time.