The graph illustrates how the resistance of a uniform metal wire changes as its length changes. The graph’s gradient is $G$. The wire has cross-sectional area $A$. Which expression could be used to calculate the resistivity of the metal in the wire?
- A$G \times A$
- B$\frac{G}{A}$
- C$\frac{A}{G}$
- D$G \times A^2$