Final answer:
The implied consent law refers to a driver's automatic agreement to undergo chemical tests for substances if suspected of DUI, just by using public roads and having a license.
Step-by-step explanation:
The implied consent law means that by the act of obtaining a driver's license and driving on public roads, a driver has agreed to submit to breath, blood, or urine testing if suspected of driving under the influence (DUI) of alcohol or drugs. Refusal to take these tests can result in penalties such as the suspension of the driver's license. Therefore, the correct answer is a. Driver agrees to take the breath test.