What safety feature related to the driver's seat must be checked during an inspection?

The adjustment and securing of the driver's seat is a crucial safety feature that must be checked during an inspection. A properly adjusted and secured driver's seat ensures that the driver can reach the controls comfortably and maintain full control of the vehicle while driving. This adjustment includes ensuring that the seat is positioned at the appropriate height and distance from the steering wheel and pedals. If the seat is not secured correctly, it could move unexpectedly during driving, potentially leading to a loss of control or an accident.

The other options, while relevant to overall vehicle maintenance and comfort, do not directly impact safety in the same way. The color and design of the seat cover, presence of a cushion, and external cleanliness do not affect the functionality or safety of the driver’s ability to operate the vehicle safely. Therefore, ensuring that the seat can be reliably adjusted and securely locked is paramount for safe vehicle operation.