Question

what is the function of the signal from terminal c of the throttle valve assembly?
this signal switches the engine off, if the opening angle of the throttle valve is too large.
this signal regulates the current through the throttle valve actuator.
this signal provides information about the position of the throttle valve, to the control unit.

Explanation:

The throttle valve assembly's terminal C signal has multiple functions. It can switch the engine off if the throttle valve opening angle is too large (safety - related). It also regulates the current through the throttle valve actuator (actuation - related) and provides position information to the control unit (feedback - related).

Answer:

This signal switches the engine off, if the opening angle of the throttle valve is too large. This signal regulates the current through the throttle valve actuator. This signal provides information about the position of the throttle valve, to the control unit.