Which metals can be used in the cathodic protection of `Fe` against rusting.

(i) Carbonate and sulphide ores are usually converted into oxides during the process of extraction of metals. (ii) Ionic compounds have generally high melting points. (iii) Hydrogen is not a metal but is has been assigned a place in the reactivity series of metals. (iv) The galvanised iron article is protected against rusting even if the zinc layer is broken.

Which among the following metals is employed to provide cathodic protection to iron ?

Some protection is provided against carcinogens by