Correct Answer (Detailed Explanation is Below)
C.
Rusting of iron
Detailed Explanation
Rusting of iron is a chemical reaction because iron reacts with oxygen and moisture to form hydrated iron(III) oxide, commonly called rust. A chemical reaction generally produces one or more new substances with different properties. Other examples include
burning of wood, digestion of food, photosynthesis and souring of milk. Melting and boiling are physical changes because no new substance is formed.