Aluminium is a silvery-white metal that is malleable and light. It's an excellent electrical conductor and amphoteric, meaning it can react with both acids and bases. When aluminium is combined with an acid, it produces aluminium salt and gaseous hydrogen in a classic single displacement reaction.

At normal temperature, aluminium combines with dilute hydrochloric acid. Aluminium chloride and colourless hydrogen gas result from the metal's dissolution in hydrochloric acid. The end products will not react with each other, hence this reaction is irreversible. An oxidation-reduction process is what happens when metallic aluminium reacts with hydrochloric acid.

Aluminium is a reducing agent, which means it gives away electrons:

These electrons are taken by the cations of hydrochloric acid, which are then reduced to molecular hydrogen:

The reaction looks like this in the molecular form: $2\mathrm{Al} + 6\mathrm{HCl} \to 2{\mathrm{AlCl}}_3 + 3{\mathrm{H}}_2\uparrow$

Hence, option A is correct.