When is it safe to pass another vehicle?

Passing another vehicle is safest when you have a clear line of sight, no oncoming traffic, and no restrictions like solid lines on the road. These conditions ensure that you can clearly see the road ahead and assess any potential hazards. A clear line of sight allows you to confirm that the lane is safe to enter and that no vehicles, pedestrians, or other obstacles might interfere with your maneuver. The absence of oncoming traffic indicates that you won’t be in danger of a head-on collision while passing. Additionally, recognizing no restrictions such as solid lines indicates that it is legally permissible to change lanes and pass the other vehicle.

In contrast, waiting for a vehicle to turn off their signal or trying to pass during heavy traffic can lead to dangerously unpredictable situations, as you might not accurately judge the intentions of others on the road. Furthermore, relying solely on checking blind spots does not guarantee safety when passing—it's essential to evaluate the overall traffic conditions and road markings as well. Thus, option A encapsulates the critical elements necessary for safe passing.