A copper specimen has resistivity equal to 1.8 x 10-8 ohm-m at room temperature. At a temperature of 700 K, the resistivity is likely to be

• 1.6 x 10-8 Ω-m
• 2 x 10-8 Ω-m
• 3 x 10-8 Ω-m
• 6 x 10-8 Ω-m