Solids have a wide range of electrical conductivities, and can be categorized into metals, insulators, and semiconductors. Metals are solids with conductivities between 10⁴ and 10⁷ ohm^-1 m^-1, with metals having conductivity in the order of 10⁷ ohm^-1 m^-1 being good conductors. Insulators are solids with low conductivities and their conductivities range from 10^-20 ohm^-1 m^-1 to 10^-10 ohm^-1 m^-1. Semiconductors are solids with conductivities in the intermediate range, between 10^-6 and 10⁴ ohm^-1 m^-1. The conductivity of metals is many degrees higher than insulators, while semiconductors have higher conductivity than insulators but lower than metals. The correct answer is (i).