Which solution produces a black precipitate when added to an aqueous copper(II) solution?

$({\mathrm{NH}}_4{)}_2\mathrm{S}$ solution produces black precipitate when added to copper(II) solution.

A copper hydroxide precipitate with a light blue colour is formed when copper (II) sulfate solution is mixed with an aqueous solution of ammonia. Tetra copper, a complex ion, is produced when this dissolves in the excess aqueous solution to produce the deep blue-coloured solution (II).

Hence, the correct option is B.