Potassium permanganate decomposes under heating conditions to produce potassium permanganate, manganese dioxide and oxygen, which cannot be decomposed at room temperature. Therefore, in the experiment of oxygen production with hydrogen peroxide solution, potassium permanganate is mistaken for manganese dioxide and mixed with it. Because there is no catalyst, the reaction speed and the amount of oxygen produced are the same as those without potassium permanganate.

So choose: C.