The pair of ions with paramagnetic nature and same number of electrons is

In which of the following transition metal ion (aquated) is not correctly matched with its colour?

Consider the following pairs of elements and identify the pairs of elements which have nearly same atomic radius.

I. Y, La

II. Zr, Hf

III. Mo, W

IV. Cr, Mo

$E_{\mathrm{M}^{3}| \mathrm{M}^{2+}}^{\circ}($ in V$)$ is highest for