Which one of the following allows a phone call to be routed over network wires?

CONCEPT: Voice over Internet Protocol (VoIP) is the technology that digitises voice signals into data packets and routes them across an IP-based data network — the very wires that carry internet traffic — instead of the dedicated circuit-switched lines of the traditional telephone network.

APPLICATION: The question asks which option lets a phone call be carried ("routed") over network wires rather than a dedicated telephone line. VoIP does exactly this: the calling device encodes the voice into IP packets that travel over the same data-network wiring used for ordinary internet traffic, and a VoIP gateway/softswitch routes those packets to the destination.

• Video Conferencing is a broader audio-visual meeting service built on top of network transport (it often uses VoIP for its audio leg); it names a use case, not the mechanism that routes a phone call over network wires.

• Teleconferencing is a generic term for any conference call carried out through telecommunication equipment; it does not specify that the call travels over data-network wires rather than the conventional telephone circuit.

• Optical Fibre is only a physical transmission medium (glass strands carrying light signals); it can carry any kind of network traffic but is not itself a call-routing technology.

So the technology that carries a phone call over network (IP) wiring is VoIP.