The set having ions

$\left.\begin{array}{l}\mathrm{Cu}^{2+}:[\mathrm{Ar}] 3 \mathrm{~d}^{9} 4 \mathrm{~s}^{0} \\ \mathrm{Cr}^{3+}:[\mathrm{Ar}] 3 \mathrm{~d}^{3} 4 \mathrm{~s}^{0} \\ \mathrm{Sc}^{+}:[\mathrm{Ar}] 3 \mathrm{~d}^{1} 4 \mathrm{~s}^{1}\end{array}\right] \begin{aligned}&\text { All are coloured and } \\&\text { paramagnetic due to } \\&\text { presence of unpaired electrons }\end{aligned}$