Considering Ellingham diagram, which of the following metals can be used to reduce alumina?

Any metal oxide with lower value of ΔG° is more stable than a metal oxide with higher ΔG°. This implies that the metal oxide placed higher in the diagram can be reduced by the metal involved in the formation of the oxide placed lower in the diagram. The relative tendency of the various metals to act as reducing agents is :Ca>Mg>Al>Cr>Zn>Fe>Cu. Thus, Mg being more reducing in nature, can reduce aluminium oxide (alumina).