Transition metal properties depend strongly on number of unpaired d-electrons because stronger metallic bonding increases melting point and atomization enthalpy.
Step 1: Set up the matching of properties. Four periodic properties of 3d transition metals are to be matched: enthalpy of atomization, density, metallic radius, and melting point. Each follows a characteristic trend tied to metallic bonding and atomic structure. Step 2: Match enthalpy of atomization (A). Stronger metallic bonding gives higher atomization enthalpy, peaking near the middle of the series. The given order $Fe>Cr>Mn$ matches property III, so $A\rightarrow III$. Step 3: Match density (B). Density rises across the series as atomic mass increases and size shrinks. The order $Co>Fe>Mn$ matches property IV, so $B\rightarrow IV$. Step 4: Match metallic radius (C). Metallic radius generally decreases across the period. The order $Ti>V>Cr$ matches property II, so $C\rightarrow II$. Step 5: Match melting point (D). Melting point depends on bond strength, with Mn low due to its stable half filled configuration. The order $Cr>V>Mn$ matches property I, so $D\rightarrow I$. Step 6: Assemble and choose. The matching $A\rightarrow III$, $B\rightarrow IV$, $C\rightarrow II$, $D\rightarrow I$ corresponds to option (4). \[ \boxed{A\text{-}III,\ B\text{-}IV,\ C\text{-}II,\ D\text{-}I\ \ \text{(Option 4)}} \]
