On a long downgrade, you should choose...?

Answer: B — lower gear than you would use going up it

When navigating a long downgrade, the ideal approach is to select a lower gear than you would typically use when ascending the hill. This allows the engine to assist in controlling the vehicle's speed through engine braking, which is crucial for maintaining safe speeds and preventing brake overheating. Using a higher gear can result in increased speed, making it harder to control the vehicle, and relying solely on the brakes can lead to brake fade or failure due to overheating. Opting for the same gear typically used for going uphill would not provide sufficient control, as this would not harness the benefits of engine braking effectively. In summary, choosing a lower gear allows for better speed management and enhances safety while descending a long hill.