According to FMVSS/CMVSS 108, what must be true about lamps and reflectors on a vehicle?

The requirement stated in FMVSS/CMVSS 108 specifies that lamps and reflectors on a vehicle must be permanently attached. This ensures that they are securely mounted and function as intended, providing vital visibility and safety features for the vehicle. Permanent attachment prevents them from becoming dislodged or lost during operation, which is critical for maintaining the vehicle's compliance with safety regulations.

In contrast to the other options, being removable would compromise the reliability and functionality of the lighting and reflective devices. Optional equipment would imply that certain vehicles might lack these essential components, which would not be compliant with the safety standards, as every vehicle needs to meet certain lighting and visibility regulations. Lastly, while some lamps and reflectors may have adjustable features for aiming or focusing, the core requirement of their permanence ensures that they serve their primary function reliably.