Answer the following question given this paragraph: The chemical reaction that is the opposite of oxidation is called reduction. Following from the notion that oxidation was originally thought to mean only the addition of oxygen, reduction was thought to be only the removal of oxygen from a substance. Many naturally occurring metal ores are present as oxides. The pure metals can be extracted by reduction. Iron is obtained from iron(III) oxide by reacting with carbon at high temperatures. Q: What chemical reaction is the opposite of oxidation? A:

Choose from: i. mutation ii. condensation iii. evaporation iv. reduction
The answer is:
iv.