In which of the following octahedral complex species the magnitude of $\Delta_0$ will be maximum?

The magnitude of crystal field stabilisation energy in octahedral field depends on :
$I.$ The nature of the ligand
$II.$ The charge on the metal ion
$III.$ Whether the metal is in the first,second or third row of the transition elements

Among the following species,the one which causes the highest $CFSE, \Delta _0$ as a ligand is

Which of the following has zero Crystal Field Stabilization Energy $(CFSE)$ value in an octahedral field?

The crystal field stabilization energy $(CFSE)$ of $[CoF_{3}(H_{2}O)_{3}]$ $(\Delta_{0} < P)$ is $:-$

Crystal field splitting energy $(CFSE)$ for $[CoCl_6]^{4-}$ is $18000 \ cm^{-1}$. The crystal field splitting energy $(CFSE)$ for $[CoCl_4]^{2-}$ will be (in $cm^{-1}$)