What is unlawful concerning the maintenance of registration plates?

Answer: B — Not cleaning the plate for visibility

Not cleaning the registration plate for visibility is indeed unlawful. In North Carolina, as in many other jurisdictions, it is crucial that registration plates are kept clean and visible at all times. This is because law enforcement relies on being able to read the characters on the plate for identification and enforcement purposes. If a plate is dirty or obstructed in any way, it can hinder the ability to recognize the plate number, which may lead to issues such as being unable to verify the vehicle's registration status or identify the vehicle involved in a crime. In contrast, adding stickers to a registration plate can sometimes be permissible depending on the type of sticker and local regulations. The use of a plastic cover on the plate can also be lawful as long as it does not obstruct the visibility of the plate details. While it is a violation to operate with an expired plate, simply replacing a plate after the expiry date pertains more to proper timing rather than maintenance issues related to visibility. Thus, the requirement for cleanliness and visibility of registration plates is essential for the legal operation of a vehicle.