The correct relationship between the `pH` of isomolar solutions of sodium oxide `(pH_(1))`, sodium sulphide `(pH_(2))`, sodium selenide `(pH_(3))` and sodium telluride `(pH_(4))` is
A. `pH_1 gt pH_2 gt pH_3 gt pH_4`
B. `pH_1 lt pH_2 lt pH_3 lt pH_4`
C. `pH_1 lt pH_2 lt pH_3 = pH_4`
D. `pH_1 gt pH_2 = pH_3 gt pH_4`