What must not be present on a vehicle's mirrors to ensure safe operation?

The presence of cracks or tarnishes on a vehicle's mirrors is detrimental to safe operation because it can significantly impair visibility. Mirrors are crucial for a driver’s ability to see behind and beside their vehicle, allowing for safe lane changes, turns, and awareness of other road users. Any distortions caused by cracks or tarnished surfaces can obstruct the correct view of surrounding traffic, increasing the risk of accidents. Maintaining clear and intact mirrors is vital for safe driving, making this option the correct emphasis when prioritizing safety in vehicle operation.

While excess dirt can also obscure visibility, and fading can affect the effectiveness of the reflective surface, cracks or tarnishes present a more critical and immediate risk that directly impacts the driver’s ability to operate the vehicle safely. The absence of a reflective surface would clearly render the mirrors unusable, but this option is more extreme and less relevant compared to the common issue of cracks and tarnishes.