What is the 'implied consent' law?

1. A law that says you agree to be tested for drugs and alcohol if you are arrested for driving under the influence
2. A law that says you agree to a search of your vehicle if you are stopped by the police
3. A law that says you agree to a background check if you apply for a job as a school bus driver
4. A law that says you agree to have your driving record monitored by your employer