Final answer:
In California, the legal limit for a DUI arrest for an underage driver is a BAC of 0.01%, representing the state's zero tolerance toward underage drinking and driving.
Step-by-step explanation:
For an underage driver in California, a blood alcohol concentration (BAC) of 0.01% or more gives authorities the legal right to arrest the individual for DUI. This very low threshold reflects the state's zero tolerance policy for underage drinking and driving. It's important to note that this limit is much lower than the 0.08% BAC level allowed for drivers 21 and older, which is the standard level for legal intoxication across most states in the U.S. Underage drinkers may face severe penalties even for trace amounts of alcohol in their system.