You are passing another vehicle. You can safely move back into your lane once you:
Correct answer: Spot both of its headlights in your rearview mirror.
Answer options
ASpot both of its headlights in your rearview mirror Correct
BNo longer see the vehicle beside you on the right
CHave moved just past its front bumper
Why
Once both headlights of the car you overtook appear in your rearview mirror, there is usually enough space to pull back in. Merely losing sight of the car, or just clearing its front bumper, leaves too little room.