Before changing lanes, what should a driver do?

Answer: B — Check mirrors and blind spot

A driver should always check their mirrors and blind spot before changing lanes. This practice ensures that they are aware of their surroundings and can detect any vehicles or obstacles that may not be visible solely through mirrors. The purpose of checking mirrors is to see vehicles behind and beside the car, while checking the blind spot is crucial because some vehicles might be in areas that mirrors do not cover. By taking this step, drivers can make informed decisions about when it is safe to change lanes, thereby reducing the risk of collisions and ensuring a safer driving environment for everyone on the road. Signaling intentions is important, but it should follow the assessment of the area for safety.