Question

which of the following metals is the best electrical conductor, but isnt used in wire because of its extremly high cost?

Answer 1

In the absence of choices above, the best conductor is pure silver with 105% conductivity rating. This could be a replacement for copper wires but pure silver is more expensive than copper; it also tarnishes easily.

Gold, which is believed to be a good conductor, is far less conductive than copper and even much lesser conductive than pure silver.