As a general rule, on a narrow road section with a steep gradient, you must give way to...

A)the ascending vehicle.
B)the lighter vehicle.
C)the descending vehicle.Correct
# Explanation
On narrow sections with a steep gradient, **the descending vehicle must give way to the ascending vehicle**. This is because it is more difficult and dangerous to resume movement uphill than to stop a vehicle going downhill. The descending vehicle can brake and reverse more easily if necessary, while the ascending vehicle requires more engine effort to regain its momentum.