Hand shunting of vehicles is prohibited in gradient A. 1 – 260 B. 1 – 400 C. 1 – 400 or steeper D. None of these

The correct answer is: C. 1 – 400 or steeper

Hand shunting of vehicles is prohibited in gradients of 1 in 400 or steeper. This is because it is dangerous to try to move a vehicle up a steep gradient by hand. The vehicle may start to roll back, and the person trying to shunt it may be injured.

Option A is incorrect because it is not a steep enough gradient to be dangerous. Option B is incorrect because it is not a complete sentence. Option D is incorrect because it is not one of the options listed.