Final answer:
For individuals under 21, most states set the blood alcohol concentration (BAC) limit at 0.00% to 0.02%, aligning with the zero-tolerance policy established by the National Minimum Drinking Age Act of 1984.
Step-by-step explanation:
The limit of alcohol in the blood for people under age 21 in most states is very stringent. In alignment with the National Minimum Drinking Age Act of 1984, which required states to either raise their drinking age to twenty-one or face potential cuts in federal highway funds, the blood alcohol concentration (BAC) level for those under 21 is typically set at 0.00% to 0.02%, effectively instituting a zero-tolerance policy. This legal standard is crucial to prevent alcohol-related incidents and promote safe driving practices among young individuals.