Final answer:
Baking powder option (b) can be substituted for baking soda as a leavening agent in a yeast bread recipe. Baking powder contains sodium bicarbonate and solid acid, which react to produce carbon dioxide gas, causing the bread to rise.
Step-by-step explanation:
If a yeast bread recipe calls for 1 teaspoon of baking soda, the ingredient that could be substituted as a leavening agent is B) Baking powder. This is because baking powder contains sodium bicarbonate (baking soda) along with a solid acid, such as potassium hydrogen tartrate (cream of tartar), which reacts with the sodium bicarbonate in the presence of water to produce carbon dioxide gas.
This carbon dioxide causes the bread to rise. In contrast, active dry yeast is a biological leavening agent that works over a longer time scale and would not be a direct substitute for the immediate leavening action of baking soda. Salt is not a leavening agent at all. Vinegar could react with baking soda to produce carbon dioxide, but it is not used as a leavening agent in this context.
When vinegar (which contains acetic acid, CH3COOH) is mixed with baking soda (sodium bicarbonate), the base that serves in the reaction is the bicarbonate ion from the baking soda. The reaction between vinegar and baking soda is an acid-base reaction where acetic acid reacts with sodium bicarbonate to produce carbon dioxide, which can help leaven the dough.