For the Reaction NH₃(g)+ H₂S(g) →NH₄HS(s)

For the reaction NH₃(g) + H₂S(g) →NH₄HS(s)
K_c = 9.7 at 900 K.If the initial concentrations of NH₃(g) and H₂S(g) are 2.0 M,what is the equilibrium concentration of H₂S(g) ?

A) 1.9 M
B) 0.20 M
C) 1.7 M
D) 0.10 M
E) 0.32 M