What should you do before making a lane change?

Before making a lane change, it is essential to signal your intentions and check both your mirrors and blind spots to ensure that it is safe to proceed. Signaling alerts other drivers of your intention to change lanes, allowing them to adjust their driving accordingly. Checking mirrors provides a view of vehicles currently alongside you, while checking blind spots helps identify any cars that may be in your immediate vicinity that are not visible in your mirrors. All these actions contribute to safer driving by minimizing the risk of collisions.

Focusing solely on signaling if there is another vehicle nearby neglects the necessary precautions when changing lanes. Turning off the radio is not a requirement for safety in this context, and simply looking in the rearview mirror does not provide a comprehensive view of the surroundings, especially the blind spots where other cars may be positioned. Thus, taking a complete approach as represented in the correct answer helps ensure both your safety and that of other drivers on the road.