Identify the weak field ligand from the following.

What is the electronic arrangement of a metal atom/ion in an octahedral complex with $d^4$ configuration,if $\Delta_0 < P$ (pairing energy)?

What is the correct order for energy of $d$ orbitals during splitting in the $[NiCl_4]^{2-}$ complex ion?

What is the electronic arrangement of a metal atom/ion in an octahedral complex with a $d^4$ configuration,if $\Delta_o < \text{pairing energy}$?

Crystal field stabilization energy for high spin $d^4$ octahedral complex is

Consider the metal complexes $[Ni(en)_3]^{2+}$ $(A)$, $[NiCl_4]^{2-}$ $(B)$ and $[Ni(NH_3)_6]^{2+}$ $(C)$. Choose the $\text{CORRECT}$ option by considering the number of unpaired electrons present in $(A)$, $(B)$ and $(C)$ respectively and the order of frequency of absorption.