Nichrome is an alloy of nickel, chromium, and iron. Nichrome wires are used as resistance heating elements in electric heaters. Resistivity of nichrome at 20°C is
a) 1.1 × 10⁻⁶ Ωm
b) 2.2 × 10⁻⁶ Ωm
c) 3.3 × 10⁻⁶ Ωm
d) 4.4 × 10⁻⁶ Ωm