The solubility of silver chloride in water is increased markedly by adding aqueous ammonia. The main reason is

Aa rise in the solubility product of AgCl in presence of $NH X_{3}$
Bthe common-ion effect of $NH X_{4} X^{+}$ on $Ag X^{+}$
Cformation of the soluble complex ion $[Ag (NH X_{3}) X_{2}] X^{+}$ , which lowers $[Ag X^{+}]$ so that more AgCl dissolves
Dammonia reacting with chloride ions to form $NH X_{4} Cl$

Answer: C

Ag X^{+}

binds

NH X_{3}

to form

[Ag (NH X_{3}) X_{2}] X^{+}

, removing free

Ag X^{+}

. To keep

[Ag X^{+}] [Cl X^{-}] = K_{s p}

, more AgCl dissolves.

K_{s p}

depends only on temperature, and no common ion is involved.