A 0.60-mm-diameter wire made from an alloy (a combination of different metals) has a conductivity that decreases linearly with distance from the center of the wire: σ(r) = σ₀ - cr, with σ₀ = 5.0 × 10⁷ Ω^-1 m^-1 and c = 1.2 × 10¹¹ Ω^-1 m^-2 . What is the resistance of a 4.0 m length of this wire?