$$NiCl_2\left\{P (C_2H_5)_2(C_6H_5)\right\}_2$$ exhibits temperature dependentmagnetic behaviour (paramagnetic/ diamagnetic). the coordination geometries of $$Ni^{2+}$$ in the paramagnetic and diamagnetic states are respectively

A

tetrahedral and tetrahedral

B

square planar and square planar

C

tetrahedral and square planar

D

square planar and tetrahedral