When you reach your destination, what must you do when leaving your vehicle?

Answer: B — Turn off the engine and take your keys

This is because it is important to turn off the engine and take your keys with you when leaving your vehicle in order to prevent theft or accidents. Exiting the vehicle before turning it off (choice A) could potentially lead to the car being left on, which is both wasteful and dangerous. Yelling out (choice C) as you exit the vehicle is unnecessary and could potentially disturb others. Making sure the parking brake is down (choice D) is a good practice, but it is not the primary action that must be taken when leaving the vehicle.