When is it permissible to pass another vehicle on the right?

Passing another vehicle on the right is permissible when the vehicle ahead is making a left turn. This is a common traffic situation where it is safe to pass, as the left-turning vehicle is momentarily occupying the left lane or is slowing down to turn, allowing drivers the opportunity to move past on the right without being in conflict with that vehicle's intended maneuver.

The reason this option is correct lies in the implications for safety and traffic flow. By allowing passing on the right in this context, it helps reduce congestion and keep traffic moving smoothly, as long as the driver has a clear view and adequate space to do so safely.

The other choices do not appropriately define the conditions for passing on the right. While it might seem that passing on a one-way street could be acceptable in certain contexts, it is not the only condition under which passing on the right is allowed. Stating that it is permissible "whenever a pass is safe" is misleading because there are specific legal guidelines dictating when passing on the right is appropriate. Finally, considering it permissible in "all situations" is impractical, as there are many scenarios where such passing could lead to confusion or accidents.