Answer: sodium hydroxide
Step-by-step explanation:
Electrolyte is a substance which dissociates into ions when dissolved in water and thus is able to conduct electric current through them. Ionic compounds dissociate in water to give ions and thus acts as electrolytes.
Compounds in solid form does not conduct electricity due to the absence of free ions.
Sodium hydroxide is an ionic compound which dissociates to give sodium and hydroxide ions.

Sugar, carbon tetrachloride, rubbing alcohol are covalent compounds and thus do not dissociate to give ions and thus do not act as electrolytes.