The complex ion having minimum magnitude of $\Delta_{0}$ $(CFSE)$ is

On what factors does the crystal field splitting in an octahedral complex depend?

The $CFSE$ for $[CoCl_6]^{4-}$ complex is $18000 \ cm^{-1}$. The $\Delta_t$ for $[CoCl_4]^{2-}$ will be ........... $cm^{-1}$.

Which of the following complexes has maximum $CFSE$?

What is crystal field splitting energy? How does the magnitude of $\Delta_{o}$ decide the actual configuration of $d$-orbitals in a coordination entity?

Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $[CoCl(NH_3)_5]^{2+}$ absorbs at a lower wavelength of light with respect to $[Co(NH_3)_5(H_2O)]^{3+}$.
Reason $R$: It is because the wavelength of the light absorbed depends on the oxidation state of the metal ion.
In the light of the above statements,choose the correct answer from the options given below: