$AgNO_3(aq)\;\overset{\overset{electrolysis}{\Large\rightarrow}}{in\;presence\;of\;Ag\;electrode}$ then wrong statement is
$\begin{array}{1 1}(a)\;Ag\;\text{deposite at cathode}\\(b)\;AgNO_3(aq)\text{Concentration will not change}\\(c)\;O_2\text{will not appear at anode}\\(d)\;None\end{array}$