The correct answer is: None of these.
During shunting, outer, home and intermediate signals are not taken off.
An intermediate signal is a railway signal that is located between two main signals. It is used to control the movement of trains between the main signals.
Shunting is the movement of railway vehicles within a railway yard or depot. It is used to assemble trains, to move wagons to and from sidings, and to load and unload wagons.
When shunting, it is important to ensure that the safety of trains and personnel is maintained. This is why intermediate signals are not taken off during shunting. Intermediate signals help to ensure that trains do not collide with each other or with other objects.
Taking off an intermediate signal means that the signal is no longer in use. This can create a hazard, as it means that trains may not be aware of the presence of other trains or objects.
Therefore, it is important to keep intermediate signals in use during shunting. This will help to ensure the safety of trains and personnel.