What must be ensured before a vehicle is turned upright in a rescue operation?

The correct choice in this scenario is that the scene must be released by law enforcement. Before turning a vehicle upright during a rescue operation, it is crucial to ensure that the area is safe and secure for rescuers and victims alike. Law enforcement typically assesses the scene for hazards and grants permission to proceed, ensuring that the area is clear of threats such as traffic or unstable hazards that could compromise safety.

Securing the scene is an essential part of the rescue operation, but that security specifically comes from law enforcement's assessment and clearance, which is why their release is vital. It ensures that all potential risks are managed and that necessary emergency protocols are being followed.

While securing the vehicle, ensuring passenger removal, and checking for fluids are all important steps in vehicle rescue operations, the immediate priority is to obtain a safe environment. Thus, law enforcement's release is a prerequisite for safety in the rescue process.