Among `TiF_(6)^(2-), CoF_(6)^(3-), Cu_(2)Cl_(2)` and `NiCl_(4)^(2-)` (At. No. `Ti = 22, Co = 27, Cu = 29, Ni = 28)`, the colourless species are -
A. `TiF_(6)^(2-)` and `Cu_(2) C1_(2)`
B. `Cu_(2) C1_(2)`
C. `TiF_(6)^(2-)` and `CoF_(6)^(3-)`
D. `CoF_(6)^(3-)` and `NiC1_(4)^(2-)`
