Which of the following wired medium will be able to have highest speed data…

A wired medium's achievable data-communication speed is set mainly by its available bandwidth and by how quickly the carried signal weakens (attenuation) with distance: media that carry information as pulses of light through a glass or plastic fiber support a far larger bandwidth and far lower attenuation than media that carry an electrical signal through a copper conductor.

Among the four options, only fiber optic cable transmits data as light pulses; the remaining three (single pair telephone cable, co-axial cable, twisted pair cable) all carry an electrical signal over copper conductors and are therefore bounded by copper's bandwidth-distance limits. Applying the concept above, the light-based medium is the one capable of the highest achievable data-communication speed.

This is confirmed independently by real-world deployment: telecom backbones and long-haul internet links are built on fiber precisely because they must reach aggregate throughputs in the multi-gigabit-to-terabit range, a scale that copper-based media cannot reach on account of their bandwidth-distance product.

• Single pair telephone cable: a single unshielded copper pair originally engineered for analog voice calls; it supports only narrow bandwidths suited to voice-band and low-rate signaling.

• Co-axial cable: a central copper conductor wrapped in an insulating layer with an outer conductive shield; the shielding supports higher frequencies than a basic telephone pair and is common for cable television and cable-internet distribution.

• Twisted pair cable: two copper conductors twisted together to reduce electrical interference between them; common categories (e.g. Cat5e/Cat6) reach multi-gigabit rates over runs of roughly 100 metres, typical of Ethernet LAN wiring.

• Fiber optic cable: carries information as pulses of light through a glass or plastic core, giving it a very large bandwidth, very low signal loss over long distances, and immunity to electromagnetic interference.

Therefore, fiber optic cable is the wired medium capable of the highest data-communication speed among the given options.