What characterizes a conductor in terms of electrical conductivity?

A conductor is characterized by its behavior in response to temperature changes, particularly in terms of electrical conductivity. In general, for metallic conductors, as temperature increases, the atoms within the metal lattice vibrate more intensely due to increased thermal energy. This higher degree of atomic vibration creates more collisions between the conduction electrons and the vibrating lattice, effectively scattering the electrons and reducing their mobility. As a result, the overall electrical conductivity of the conductor decreases with increasing temperature.

This behavior is distinct from materials like semiconductors or insulators, where conductivity can increase with temperature due to the promotion of charge carriers. Therefore, the characteristic of conductivity decreasing as temperature increases accurately captures the fundamental behavior of good electrical conductors, which is why this is the correct answer.

In contrast, the other options do not reflect the general behavior of conductors. An increase in conductivity with temperature does not apply to typical metallic conductors. The idea that conductivity remains constant regardless of temperature or is independent of the material also fails to capture the essential properties of conductors, as their conductivity is very much dependent on the material's structure and the temperature.