Hydrogen gas is evolved during the reaction between Copper and dilute hydrochloric acid Magnesium and oxygen Aluminium and sodium hydroxide Sulphur and dilute hydrochloric acid

Hydrogen gas will be evolved when aluminium reacts with sodium hydroxide.It is found that aluminium dissolves in sodium hydroxide with the evolution of hydrogen gas, H2, result in the formation of aluminates ion [Al(OH)4]-.

2Al(s) + 2NaOH(aq) + 6H2O → 2Na+(aq) + 2[Al(OH)4]- + 3H2(g)

Thus option (3) will be correct.