A compound formed by Mg, Al and O, is found to have cubic close array of oxide ions in which $$Mg^{2+}$$ occupying $$\frac {1}{8}th$$ of tetrahedral voids and $$Al^{3+}$$ ions occupying $$\frac{1}{2}$$ the octahedral voids. The formula for the compound is

A

$$MgAlO$$

B

$$MgAl_4O_2$$

C

$$Mg_2Al_3O_2$$

D

$$MgAl_2O_4$$