For the reaction [Ag(CN)2]- ⇌ Ag+ + 2CN- , the equilibrium constant Kc , at 25°C is 4.0 x 10-19 then the silver ion concentration in a solution which was originally 0.1 molar in KCN and 0.03 molar in AgNO3 is
a. 7.5 x 1018
b. 7.5 x 10-18
c. 7.5 x 1019
d. 7.5 x 10–19