Which element of the $3d$-series has the highest third ionisation enthalpy?

$A$ chloro compound of vanadium has a spin-only magnetic moment of $1.73 \ BM$. This vanadium chloride has the formula:

Which of the following statements are correct about $Zn, Cd$ and $Hg$?
$A$. They exhibit high enthalpy of atomization as the d-subshell is full.
$B$. $Zn$ and $Cd$ do not show variable oxidation state while $Hg$ shows $+I$ and $+II$.
$C$. Compounds of $Zn, Cd$ and $Hg$ are paramagnetic in nature.
$D$. $Zn, Cd$ and $Hg$ are called soft metals.
Choose the most appropriate from the options given below:

Which of the following elements is $NOT$ regarded as a transition element?

What is the characteristic valence shell electronic configuration of the elements of group $11$?

Most stable cation in aqueous medium is