Metals which do not react with dilute acids:  

In diluted acids, there is a lot of water. Water is used to dilute concentrated acids. In reality, an acid is a chemical that releases hydrogen ions (i.e. H+
) when it dissolves in water.
Metals that are reactive, such as magnesium, zinc, aluminum, and iron, typically react with diluted acids. A salt and hydrogen gas are created as a result of the reaction. The name of the acid determines the name of the salt. The phrase "MASH" i.e.

$(M+A\to S+H)$
For instance, when magnesium or zinc reacts with hydrochloric acid or sulphuric acid, they produce the corresponding salts and hydrogen gas, respectively. The following illustrates the responses:
$\mathrm{Mg}+2\mathrm{HCl}\to {\mathrm{MgCl}}_2+{\mathrm{H}}_2$
$\mathrm{Zn}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{ZnSO}}_4+{\mathrm{H}}_2$

The reactivity of the metal directly affects the velocity of the reaction; the more reactive the metal, the faster the reaction. We are basically given three metals in the question: copper, silver, and mercury. These three elements are all significantly less reactive when compared to other metals in the reactivity series because they do not readily oxidize (or, alternatively, readily donate electrons). Copper, silver, and mercury will not displace the hydrogen from the non-metal anion, hence they cannot react with the diluted acid.

Hence, the correct answer is option D.