Step 1: Understanding the composition.
Baking powder is a mixture that typically contains starch, sodium hydrogen carbonate (baking soda), and an acidifying agent, which is potassium hydrogen tartrate. It is used as a leavening agent in baking.
Step 2: Analyzing the options.
(A) Baking soda: Incorrect. Baking soda consists of sodium bicarbonate alone and does not contain starch or potassium hydrogen tartrate.
(B) Caustic Soda: Incorrect. Caustic soda is sodium hydroxide (NaOH), which is not part of this mixture.
(C) Washing Soda: Incorrect. Washing soda is sodium carbonate, which is not part of this mixture.
(D) Baking Powder: Correct — Baking powder contains sodium hydrogen carbonate, starch, and an acidifying agent like potassium hydrogen tartrate.
Step 3: Conclusion.
The correct answer is (D) Baking Powder, as it is the mixture of starch, sodium hydrogen carbonate, and potassium hydrogen tartrate.