OPT: [i] carbon monoxide; [ii] oxygen; [iii] hydrogen; [iv] carbon dioxide;
Given those answer options, answer the question: Answer the following question given this paragraph: When bread bakes, yeast releases carbon dioxide gas, forming the small holes in bread. The gas was produced by alcoholic fermentation carried out by yeast. Q: When bread bakes, yeast releases which gas? A:
A:
[iv]