Complete the following by selecting the correct option from the choices given :
(i) The metal which does not react with water or dilute H2SO4 but reacts with concentrated H2SO4 is ......... (Al/Cu/Zn/Fe)
(ii) The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction ........... ( Fe / Mg / Pb / Al)
(iii) The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is ........... (Al/Na/Mg/K)