What could lead to a vehicle being deemed "unroadworthy"?

A vehicle is deemed "unroadworthy" when it has serious deficiencies that significantly impair its safe operation. This could include issues such as brake failure, severe tire wear, or problems with critical systems like steering or suspension. These deficiencies pose a direct risk to the safety of the driver, passengers, and other road users, which is the main criterion for a vehicle to be declared unroadworthy.

Cosmetic damage, such as dents or scratches, does not impact the functionality or safety of a vehicle, therefore it cannot lead to the vehicle being classified as unroadworthy. Similarly, minor scratches on the paint or high fuel consumption levels, while they may indicate other issues or inconveniences, do not compromise the essential functionalities or safety features necessary for the vehicle to operate safely on the roads.

In summary, the emphasis is on the serious nature of deficiencies that affect the safety mechanisms or operational capabilities of the vehicle, which is why that answer is the correct choice.