What should manhole covers be like before driving over them?

Answer: B — Closed

Manhole covers should be closed before driving over them to ensure safety and prevent any potential hazards. A closed manhole cover creates a barrier that secures the opening beneath it, reducing the risk of debris, accidents, or damage to the vehicle. Open or ajar covers present significant dangers, as they can lead to falls into an open hole or potential vehicle damage. Additionally, non-existent manhole covers would typically indicate a major safety issue, exposing drivers to the risk of falling into an unprotected and open space on the road. Therefore, ensuring that manhole covers are closed is a critical aspect of safe vehicle operation.