The Most Useful Ore of Aluminum Is Bauxite,in Which Al

The most useful ore of aluminum is bauxite,in which Al is present as hydrated oxides, The number of kilowatt-hours of electricity required to produce of aluminum from electrolysis of compounds from bauxite is ________ when the applied emf is

A) 0.0213
B) 0.0469
C) 31.3
D) 15.6
E) 46.9