The acidic nature of hydrogens in acetylene can be explained by the reaction with 

i) Sodium metal 

ii) Ammoniacal cuprous chloride solution 

iii) Ammoniacal silver nitrate solution 

The acidic nature of hydrogens in acetylene can be explained when,

• Acetylene reacts with sodium metal in the presence of liq. Ammonia to give sodium acetylide where Na replaces the two hydrogens in the $\mathrm{HC}\equiv \mathrm{CH}$.
• when acetylene reacts with ammoniacal cuprous chloride solution and ammoniacal silver nitrate solution the $\mathrm{Cu}$ from $\mathrm{AgCuCl}$, replaces the hydrogens of acetylene to form copper acetylide and silver from ammoniacal silver nitrate solution replaces the hydrogens to form silver acetylide. Hence, explaining the acidic nature of the hydrogens. 

i) $\mathrm{HC}\equiv \mathrm{CH}+2\mathrm{Na}$ . $\stackrel{ \mathrm{in} \mathrm{liq} {\mathrm{NH}}_3}{\to }\mathrm{NaC}\equiv \mathrm{CNa}+{\mathrm{H}}_2$

ii) $\mathrm{HC}\equiv \mathrm{CH}+{\mathrm{AgCuCl}}_2+2{\mathrm{NH}}_4\mathrm{OH}\to \mathrm{CuC}\equiv \mathrm{CCu}+2{\mathrm{NH}}_4\mathrm{Cl}+2{\mathrm{H}}_2\mathrm{O}$

iii) $\mathrm{HC}\equiv \mathrm{CH}+2{\mathrm{AgNO}}_3+2{\mathrm{NH}}_4\mathrm{OH}\to \mathrm{AgC}\equiv \mathrm{CAg}+2{\mathrm{NH}}_4{\mathrm{NO}}_3+2{\mathrm{H}}_2\mathrm{O}$

Therefore, option (D) is correct.