Rusting of iron is catalysed by which of the following?

What is observed on the corrosion of $Fe$,$Cu$,and $Ag$ metals?

Given below are two statements:
Statement $I$: Corrosion is an electrochemical phenomenon in which pure metal acts as an anode and impure metal as a cathode.
Statement $II$: The rate of corrosion is more in alkaline medium than in acidic medium.
In the light of the above statements,choose the correct answer from the options given below:

Rusting of iron is catalyzed by which of the following?

The metal that forms a self-protecting film of oxide to prevent corrosion is

Aluminium is more reactive than iron. But aluminium is less easily corroded than iron because