Given the balanced equation representing a reaction:
4Al(s) + 3O2(g) ==> Al2O3(s)
As the aluminum loses 12 moles of electrons, the oxygen
(1) gains 4 moles of electrons
(2) gains 12 moles of electrons
(3) loses 4 moles of electrons
(4) loses .12 moles of electrons

 As  aluminium   loses 12 moles  of electrons  oxygen   gain  12 moles of electrons.Explanation  4Al +  3 O2→ Al2O3  first write the ions of  Aluminium  and  oxygen that is, Aluminium  ion is = Al^3+              oxygen   ion  is =  O^2-therefore  one  atom  of Al   loses   3  electrons  moles  while                one atom of  O gain  2  electrons  moles                from equation above there  a total of number of Al atom are 4 =( 1 x4=4)  atoms   while                                                Oxygen atoms  are  6= ( 3 x2=6) atoms therefore the total  number of Moles of Al lost is = 3  x 4 = 12 moles of                       electrons       total  number of moles of O gained  =  2 x6 = 12 moles  of electrons

Base on the question, which of the following that sates the balance of the reaction and as the aluminum loses 12 moles of electrons, what could be the oxygen, and base on my research, the possible answer among them is in number (2) gains 12 moles of electrons, I hope you are satisfied with my answer and feel free to ask for more