Alcohol concentration means the number of grams of alcohol per how many milliliters of urine?

The correct answer is that alcohol concentration is measured as the number of grams of alcohol per 100 milliliters of urine. This standard measurement allows for consistent and comparable results when testing for alcohol concentration in urine.

The basis for this standard comes from various medical and legal contexts where understanding the amount of alcohol relative to a specific volume is crucial. Typically, urine testing for alcohol serves as one method to assess an individual's level of intoxication, helping authorities make informed decisions regarding health and safety laws.

Other volume options do not reflect the conventional units used in scientific measurement for alcohol concentration in urine, making them less relevant in this context. Therefore, the choice of 100 milliliters is the correct one as it aligns with established practices for quantifying substances in biological samples.