The correct answer is: Yeast is added.
Yeast is a living organism that converts sugar into carbon dioxide and alcohol. The carbon dioxide bubbles cause the dough to rise.
Alcohol is not added to bread dough, as it would give the bread a bitter taste.
Carbon dioxide is passed through the dough in some industrial bread-making processes, but this is not the traditional way to raise dough.
Air is not passed through the dough, as this would not cause it to rise.
Here is a more detailed explanation of each option:
- Option A: Alcohol is added.
Alcohol is not added to bread dough, as it would give the bread a bitter taste. Alcohol is produced as a byproduct of the yeast fermentation process, but it is not added to the dough intentionally.
- Option B: Yeast is added.
Yeast is a living organism that converts sugar into carbon dioxide and alcohol. The carbon dioxide bubbles cause the dough to rise. Yeast is the traditional way to raise bread dough.
- Option C: Carbon dioxide is passed through the dough.
Carbon dioxide is passed through the dough in some industrial bread-making processes. This is done to speed up the rising process and to create a more uniform texture in the bread. However, this is not the traditional way to raise dough.
- Option D: Air is passed through the dough.
Air is not passed through the dough, as this would not cause it to rise. The dough needs to be sealed in order to trap the carbon dioxide bubbles produced by the yeast.