Amongst the given set of reactants, the most appropriate for preparing 2° amine is _____.
(i) 2° R—Br + NH3
(ii) 2° R—Br + NaCN followed by H_2/Pt

(iii) 1° R—NH_2 + RCHO followed by %H_2/Pt  (iv) 1° R—Br (2 mol) + potassium phthalimide followed byH_3O+$/heat