Among Cu, Al, Fe and Hg, the BEST conductor of electricity at room temperature is:

1. Resistivity order (lowest first): Ag < Cu < Al < Au < Fe < Hg. 2. Among the four given, Cu has the lowest resistivity. 3. That's why copper is the standard household-wiring material. _Source: NCERT Class 10 Science Ch 11 Table 11.2 Resistivity of Materials_