Iron reacts with dilute hydrochloric acid to produce iron(II) chloride, $\text{FeCl}_2$. Iron also reacts with chlorine to produce iron(III) chloride, $\text{FeCl}_3$. Which property of transition elements is demonstrated by this information?
- ATransition elements have high melting points.
- BTransition elements can act as catalysts.
- CTransition elements have variable oxidation states.
- DTransition elements have coloured compounds.