If a car approaches from the rear and then disappears from your mirror, what should you do before changing lanes?

Answer: C — Check your blind spot to ensure the car isn't there

When a car approaches from the rear and then disappears from your mirror, it's essential to check your blind spot before changing lanes. This behavior of the approaching vehicle may indicate that it is no longer visible in your mirrors, possibly because it has moved into your blind spot. Blind spots are areas around your vehicle that cannot be easily seen through mirrors. To ensure safety, checking your blind spot involves turning your head to look over your shoulder in the direction you intend to move. This precaution helps confirm that there are no vehicles or obstacles present that might cause a collision when you change lanes. While using your turn signal is important for informing other drivers of your intentions, it alone does not ensure that the lane change is safe, especially if another vehicle is in your blind spot. Quick lane changes may lead to dangerous situations if a car has unexpectedly moved to an area you can't see. Therefore, verifying your blind spot is the most reliable way to ensure a safe maneuver.