Final answer:
An unsafe vehicle can be put out of service until it is repaired by either the driver or the owner and passes a subsequent safety inspection.
Step-by-step explanation:
When a vehicle is deemed unsafe, it is typically put out of service until the necessary repairs are made to make it safe once again. Whether it's the driver or the owner who is responsible for fixing the vehicle can vary depending on the situation and the jurisdictions involved. Generally, the answer to the question 'How long can an unsafe vehicle be put out of service?' would be D. Either B or C, meaning the vehicle can be put out of service until either the driver fixes it or the owner fixes it. The essential factor is that the vehicle must pass a subsequent inspection indicating that the safety issues have been addressed satisfactorily before it can return to service.