Nickel (Z=28) combines with a uninegative monodenatate ligands to form a diamagnetic complex `[NiL_(4)]^(2-)`. The hybridisation involved and the number of unpaired electrons present in the complex are respectively:
A. `sp^(3)`, two
B. `dsp^(2)`,zero
C. `dsp^(2)`, one
D. `sp^(3)`, zero
