Can audible signals be used for overtaking?

A)Yes, both inside and outside built-up areas.
B)No, in no case.
C)Yes, outside built-up areas.Correct
The horn can be used both inside and outside built-up areas to avoid accidents or running someone over, when performing an urgent service and on narrow roads with many curves.
Outside built-up areas it can be used to warn of overtaking.
Outside built-up areas it can be used to warn of overtaking.