Amalgamations. Again

Chemistry Level 1

Aluminium can form an amalgam with mercury. However, when I put drops of liquid mercury on a solid aluminium, no reaction occurs.

Which is the most probable explanation of this situation?

Solid aluminium cannot form amalgamation with mercury Mercury is too volatile so it evaporates before it can react with the aluminium There is a layer of mercury oxide between the substances There is a layer of aluminium oxide between the substances