For registration purposes under German law, which document is required as proof of automobile insurance?

The requirement for an insurance confirmation card as proof of automobile insurance is rooted in German law, which mandates that vehicle owners provide clear evidence of valid insurance coverage before registering their vehicle. The insurance confirmation card, often referred to as the "eVB-Nummer" (Electronic Insurance Confirmation Number), serves as a designated form that confirms the vehicle's insurance status, ensuring that it meets the legal requirements for operating a motor vehicle in Germany.

This document is specifically designed for this purpose, allowing authorities to quickly verify that the vehicle is insured. The other options, while related to vehicle operation or ownership, do not fulfill the specific legal requirement for registration. The insurance policy itself tends to be a more comprehensive document that outlines the terms and conditions of coverage but isn't typically used directly for registration purposes. Similarly, a driver's license and the state registration document serve different functions in the driving process and do not provide proof of insurance. Therefore, the insurance confirmation card is the correct document required by law for vehicle registration in Germany.