Which graph best represents the relationship between conductivity and resistivity for a solid?

A solid conductor has a cross section area $1 {\mathrm{cm}}^2$ and $2 {\mathrm{cm}}^2$ as shown in the figure. A current of $20 \mathrm{A}$ is entering at $A$. Then,

$\mathrm{I} - \mathrm{V}$ graphs for two different electrical appliances $P$ and $Q$ are shown in the diagram. If ${\mathrm{R}}_{\mathrm{P}}$ and $R_{\mathrm{Q}}$ be the resistances of the devices, then

Variation of current passing through a conductor as the voltage applied across its ends as varied is shown in the adjoining diagram. If the resistance $\left(R\right)$ is determined at the points $A, B, C$ and $D$, we will find that