If the K_f of $\mathrm { AgCl } _ { 2 } ^ { - }$

Multiple Choice

If the K_f of $\mathrm { AgCl } _ { 2 } ^ { - }$ is 1.1×10⁵ and the equilibrium constant of the reaction is 1.9×10^-5, what is the K_sp of AgCl at $25 ^ { \circ } \mathrm { C }$ ?

A) 4.6×10^-10
B) 8.4×10^-10
C) 6.2×10^-11
D) 1.7×10^-10
E) 2.5×10^-11