In computer networking, which type of wired transmission medium has a core of refined glass?

Optic fibre carries data as pulses of light through a core made of highly refined glass.

Coaxial cable uses a solid copper core surrounded by insulation and shielding, not glass.

Shielded twisted pair uses paired copper wires wrapped in a protective metal shield against interference.

Unshielded twisted pair also uses copper wire pairs but without the extra metal shielding.

Because it transmits light rather than electricity, optic fibre resists electromagnetic interference.

Its glass core supports very high bandwidth over long distances with little signal loss.