When changing lanes, the driver should:

Answer: C — Signal and move slowly into the new lane

Drivers should always signal before changing lanes to give other drivers a heads up and avoid potential collisions. Simply relying on mirrors and turning one's head to check for traffic may not always effectively communicate intention to other drivers. Additionally, speeding up and moving quickly into a new lane can be dangerous and may surprise other drivers, while blindly moving into a new lane without signaling or checking mirrors and blind spots can lead to accidents. Therefore, the best and safest option is to signal and move slowly into the new lane, being aware of other vehicles and their movements.