A block of carbon, 1.0 cm by 2.0 cm by 5.0 cm, has a resistance of 0.015 ohms between its two smaller faces. What is the resistivity of carbon?

a) 1.5 x 10⁻⁴ ohm·m
b) 3.0 x 10⁻⁴ ohm·m
c) 6.0 x 10⁻⁴ ohm·m
d) 1.2 x 10⁻³ ohm·m