The correct option is A neutralisation
When an acid and a base react to form salt and water, the reaction is called the neutralisation reaction.
Neutralisation means to nullify each other's effect. Heat is evolved during this reaction.
For example, hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) and gives water and sodium chloride (NaCl), which is a salt. The reaction is given below:
HCl(aq)+NaOH(aq)→NaCl(aq)+H2O(l)