Match the complex ions in List-I with their geometry and magnetic character in List-II (use atomic numbers: Fe 26, Co 27, Ni 28; spin-only formula…

P: $\mathrm{Fe^{2+}}$ is $d^6$; $\mathrm{H_2O}$ is a weak-field ligand, so high spin, $t_{2g}^4e_g^2$, 4 unpaired electrons, $\mu=\sqrt{24}=4.90$ BM, octahedral: 3. Q: $\mathrm{Co^{3+}}$ is $d^6$; $\mathrm{NH_3}$ is strong enough for low spin $t_{2g}^6$, 0 unpaired, diamagnetic octahedral: 4. R: $\mathrm{Ni^{2+}}$ is $d^8$; chloride is a weak-field ligand, giving tetrahedral geometry with 2 unpaired electrons, $\mu=\sqrt8=2.83$ BM: 2. S: $\mathrm{CN^-}$ is a strong-field ligand which pairs the $d^8$ electrons, giving $dsp^2$ square planar, diamagnetic: 1. Thus P→3, Q→4, R→2, S→1. Option 5 ($1.73$ BM, one unpaired electron) matches none of the four.