The Equilibrium Constant,K_c,for the Decomposition of Ammonium Hydrogen Sulfide Is $\times$

The equilibrium constant,K_c,for the decomposition of ammonium hydrogen sulfide is 1.8 $\times$ 10^-4 at 25 ^$\circ$ C.NH₄HS(s) NH₃(g) + H₂S(g)
If excess NH₄HS(s) is allowed to equilibrate at 25 ^$\circ$ C,what is the equilibrium concentration of NH₃?

A) 3.2 $\times$ 10^-8 M
B) 9.0 $\times$ 10^-5 M
C) 1.8 $\times$ 10^-4 M
D) 6.7 $\times$ 10^-3 M
E) 1.3 $\times$ 10^-2 M