Solid Sodium Iodide Is Slowly Added to a Solution That

Solid sodium iodide is slowly added to a solution that is 0.0050 M Pb²⁺ and 0.0050 M Ag⁺. [K_sp (PbI₂) = 1.4 *10^-8; K_sp (AgI) = 8.3 *10^-17] Calculate the Ag⁺ concentration when PbI₂ just begins to precipitate.

A) 3.0 * 10^-14 M
B) 5.0 * 10^-14 M
C) 7.0 * 10^-14 M
D) 9.0 * 10^-14 M
E) None of the above