When is it safe to return to your driving lane after passing another vehicle?

The correct choice is based on ensuring that you have adequately cleared the vehicle you just passed before merging back into your lane. By waiting until you can see the front of the other vehicle in your rear view mirror, you have a clear indication that there is sufficient space between your vehicle and the vehicle you have passed. This visibility reduces the risk of cutting off the other vehicle, which could lead to a collision.

The other options might not provide a sufficient safety margin. For example, simply being two seconds ahead of the vehicle could lead to inadequate spacing if it is not a straight line distance or if the speed differential is not taken into account. Relying on seeing the front bumper could also be misleading in terms of safe distance since it might not account for the actual space required for a safe return to the lane. Lastly, waiting for the vehicle behind you to honk is not a proactive safety measure and may create unnecessary confusion and lead to dangerous situations. Thus, the focus remains on visible confirmation in your rear view mirror for a safe merging decision.