A carousel can be made to rotate using different sources of energy. One may decide to use electric energy, manual effort, water energy or heat energy as in a candle carousel.
When the candle is lit, heat energy is supplied and warm air rises heating up the air near the carousel eventually causing it to start rotating.
Hence heat from the candle leads to a current of warm air that rises up, causing the carousel to start rotating.
KMnO4 has the incorrect set of oxidation numbers. Whenever there is an alkali metal, it has an oxidation number of +1. As you can see, K is said to have an oxidation number of +2, so it is incorrect.