Question

why should you chock (block) the wheels of a tractor - trailer before loading or unloading?
the trailer could move away from the loading dock.
the dock board may not fit between the loading dock and trailer.
the wheels do not need to be chocked.
the lift truck could go through the floor of the trailer.

Explanation:

Chocking the wheels prevents the trailer from moving. If the trailer moves away from the loading dock during loading or unloading, it can cause safety hazards. The dock board may not fit properly if the trailer moves. The lift - truck going through the floor is not related to wheel chocking. Saying the wheels do not need to be chocked is incorrect as it is a safety practice.

Answer:

The trailer could move away from the loading dock.