What does a Blood Alcohol Concentration (BAC) of 0.10 percent indicate?

A Blood Alcohol Concentration (BAC) of 0.10 percent indicates that there are 0.10 grams of alcohol in every 100 milliliters of blood. This measurement is used to quantify the amount of alcohol present in a person's bloodstream and is critical in determining levels of intoxication.

The correct answer conveys that the concentration is based on a ratio where the amount of alcohol is compared to the volume of blood. A BAC of 0.10 percent means that for every 100 parts of blood, there is 0.10 part of alcohol. This threshold is significant as it can affect a person's ability to drive and may result in legal penalties. Understanding BAC is essential for responsible alcohol service and consumption, especially in relation to safety regulations and driving laws.

The alternative options fail to accurately represent the definition of BAC or confuse the ratio of alcohol to blood in different ways.