Question

An aqueous solution of sodium hydroxide conducts electricity due to:

Answer 1

Sodium hydroxide on dissociation in water produces $N{a}^{+}$ ions and $O{H}^{-}$ ions.
Each electrode attracts ions that are of the opposite charge. Positively charged ions, or cations, move toward the electrode which is negative and negatively charged ions, or anions, move toward the positive anode.​
So, the presence of both these ions are responsible for the flow of current.