The acid with highest ${\mathrm{P}}^{{\mathrm{k}}_{\mathrm{a}}}$ value is

K_a $\propto$ Acidic strength , thus lesser K_a and higher ${\mathrm{P}}^{{\mathrm{k}}_{\mathrm{a}}}$ means lesser acidic strength ;
-CH₃ at meta position . . . +I effect . . .EDG 
-OCH₃ at para position . . .-I, +M (-I < +M) . . .EDG
-NO₂ at para posotion. . .-I, -M . . .EWG
Electron donating power of -OCH₃ > -CH₃ 
EDG decrease acidic strength;
EWG increase acidic strength ;