When you are driving a truck down a steep descent:

1. Drive down on high gear and stop the vehicle every few kilometers.
2. Drive down on neutral gear and use the brakes according to need.
3. Correct answer: Drive in an appropriate low gear and make sure that the vehicle’s special deceleration mechanisms are operating.
4. The use of gears to brake the vehicle is of no significance.

WhyOn a steep descent a truck drives in a suitable low gear and uses its special deceleration mechanisms. Going down in neutral is not allowed.