A substance is classified as an electrolyte because
(1) it has a high melting point
(2) it contains covalent bonds
(3) its aqueous solution conducts an electric current
(4) its aqueous solution has a pH value of 7
The answer is (3) its aqueous solution conducts an electric current. The definition of electrolyte is a substance that will ionize when dissolved in suitable ionizing solvents such as water.