What type of materials can obstruct a driver's view from windows?

The correct answer is that non-transparent materials can obstruct a driver's view from windows. Non-transparent materials, such as certain types of tinting films, window coverings, or even items placed on the dashboard or hangings from the rearview mirror, can significantly impair visibility. For safe driving, it's essential that the driver has a clear view through all windows, as any obstruction can hinder their ability to see the road and other vehicles, increasing the risk of accidents.

While other choices mention various forms of obstructions, not all coatings or decorations impede visibility in the same way, and larger stickers alone are not the sole elements affecting a driver's field of vision. Non-transparent materials are the most definitive category that directly relates to something blocking a driver's view, making it crucial to avoid having such materials on windows to ensure safety on the road.