Look at the following table.

The above table gives the resistivity of some common materials used as conductors at a fixed temperature. The best conductor shown in the table is

The correct answer is: Silver

Resistivity is a property of a material that is useful for comparing the current carrying capacity of the material.
Lower the resistivity of a material, the lower the resistance provided to the current by that material.
Resistivity is the resistance of a conductor across a unit cross-sectional area per length.
It is denoted with the Greek letter 'rho'.
In the above table, Silver has the lowest resistivity, thus it is the best conductor.