What does a "no turn on red" sign indicate?

A "no turn on red" sign clearly indicates that drivers must wait for the green light before making a turn at the intersection. This restriction helps ensure the safety of pedestrians and other vehicles that may be crossing the intersection when the light is red. It is crucial for maintaining traffic flow and reducing the risk of collisions.

While other options may describe different situations regarding turning at a red light, they do not accurately reflect the specific regulation that a "no turn on red" sign enforces. In this case, the requirement is unequivocal: turning is not allowed until the traffic signal changes to green, ensuring that all road users can navigate the intersection safely.