Electrolytic reduction cell used for conversion of calcined Al2O3 to Al is a carbon lined furnace operating at 800-900 °C. The purpose of electric current supplied to the furnace is to___________________?

A. Achieve very high purity of aluminium (99.9%)
B. Keep the electrolyte in liquid condition by the generation of heat
C. Electrolytically dissociate alumina
D. Both B. & C.