What should you always check when changing lanes on a multi-lane road?

Answer: A — The lane next to you

When changing lanes on a multi-lane road, it's critical to always check the lane next to you. This involves being aware of the traffic in that lane, including cars, motorcycles, and bicycles, and ensuring there is enough space for you to safely maneuver into that lane. Observing the adjacent lane helps you avoid collisions and maintain the safety of both yourself and other road users. In this context, checking other factors like traffic light status, weather conditions, or fuel level is less pertinent when you're actively engaged in changing lanes. While those aspects are important for overall safe riding, they do not specifically pertain to the immediate action of changing lanes, where visibility and awareness of other vehicles are paramount.