Calculate the Equilibrium Constant K_c for the Net Reaction Shown $\leftrightharpoons$

Multiple Choice

Calculate the equilibrium constant K_c for the net reaction shown below.AgI(s) + 2NH₃(aq) $\leftrightharpoons$ Ag(NH₃) ₂⁺(aq) + I^-(aq)
For AgI, K_sp = 8.3 * 10^-17; for Ag(NH₃) ₂⁺, K_f = 1.5 * 10⁷.

A) 1.2 * 10^-9
B) 1.4 * 10^-9
C) 1.6 * 10^-9
D) 1.8 * 10^-9
E) None of the above