Iron is a transition element. transition elements that make them different from non-transition metals such as magnesium.​

Transition metals differ from the non-transition metals such as magnesium in the following ways;

They have variable oxidation statesFormation of complex ions.Formation of colored ions.Transition metals both in the elemental and compound forms can serve as catalysts.

Explanation:

Transition elements comprise of those elements in the d-block of the periodic table and which have incompletely-filled d-orbitals.

The transition elements are all metals and has the characteristic physical properties of metals such as;

high melting and boiling points,good conductors of heat and electricity,metallic lusterhigh densitiesmalleability and ductility

However, their chemical properties differ from those of the non-transition metals such as magnesium in the following ways;

They have variable oxidation states - the transition metals exhibit variability in their oxidation states because of the close similarity in the energies of the 4s and 3d electrons which are available for bond formation. For example, while magnesium has only one oxidation state of +2, vanadium a transition metal can have oxidation states of +2, +3, +4 and +5.Formation of complex ions - A complex ion consists of a central metal atom or ion to which several other atoms, ions or molecules are bonded. For example, blue tetramine copper (ii) ion, [Cu(NH₃)]²⁺.Formation of colored ions - unlike non-transition metal ions, the ions of transition metals are usually colored. For example, Copper (ii) ions, Cu⁺ are blue, Chromium (ii) ions, Cr³⁺, are green, etc.Transition metals both in the elemental and compound forms can serve as catalysts. For example, finely divide nickel serves as a catalyst in the hydrogenation of vegetable oil to margarine, while vanadium (v) oxide serves as a catalyst in the contact process for the manufacture of tetraoxosulfate (i) acid.

The answer is probably c. xylem