The graph which represents the following reaction is :
${\left({\mathrm{C}}_6{\mathrm{H}}_5\right)}_3\mathrm{C}-\mathrm{Cl}\underset{\mathrm{Pyridine}}{\overset{{\mathrm{OH}}^{-}}{\to }}{\left({\mathrm{C}}_6{\mathrm{H}}_5\right)}_3\mathrm{C}-\mathrm{OH}$

${\left({\mathrm{C}}_6{\mathrm{H}}_5\right)}_3\mathrm{C}-\mathrm{Cl}\underset{\mathrm{Pyridine}}{\overset{{\mathrm{OH}}^{-}}{\to }}{\left({\mathrm{C}}_6{\mathrm{H}}_5\right)}_3\mathrm{C}-\mathrm{OH}$
The above reaction is an example of nucleophilic substitution reaction of the type SN¹ , where the rate of the reaction is proportional to the concentration of alkyl halide but not on the concentration of nucleophile 
R=K [alkyl halide]
Hence $\mathrm{R}=\mathrm{K}\left[{\left({\mathrm{C}}_6{\mathrm{H}}_5\right)}_3\mathrm{C}-\mathrm{Cl}\right]$
Correct graph is