Final answer:
When changing lanes, it is important to check your mirrors before the lane change, after signaling and as you start the lane change, and finally after completing the lane change; therefore, the answer is D. all of the above.
Step-by-step explanation:
The question is about the proper procedure for changing lanes while driving. When changing lanes, you must always ensure safety and attentiveness throughout the maneuver. Therefore, the correct answer to the question is A. before you change lanes, which means you should check your mirrors to see the traffic condition and to ensure it is safe before commencing the lane change. Furthermore, it is essential to check the mirrors B. after you signal and as you begin the lane change to make sure the lane is clear and other drivers are aware of your intentions. Lastly, C. after you complete the lane change, a quick check in the mirrors will help you confirm you have safely entered the lane and that you are at a safe distance from other vehicles. Hence, the correct answer is D. all of the above.