When a metal rod M is dipped into an aqueous colourless concentrated solution of compound N, the solution turns light blue. Addition of aqueous `NaCI` to the blue solution gives a white precipitate O. Addition of aqueous `NH_(3)` dissolves O and gives an intense blue solution.
The final solution contains:
A. `[Pb(NH_(3))_(4)]^(2+)` and `[CoCI_(4)]^(2-)`
B. `[AI(NH_(3))_(4)]^(3+)` and `[Cu(NH_(3))_(4)]^(2+)`
C. `[Ag(NH_(3))_(2)]^(+)` and `[Cu(NH_(3))_(4)]^(2+)`
D. `[Ag(NH_(3))_(2)]^(+)` and `[Ni(NH_(3))_(6)]^(2+)`
