Which of the following emits radiation?

The correct choice identifies the microwave as an emitter of radiation. Microwaves utilize electromagnetic radiation to heat food. This process involves the production of microwave energy, which excites water molecules in the food, creating heat that cooks it. The radiation emitted in a microwave is specifically non-ionizing radiation, which is safe for cooking food.

Other appliances listed, such as the stove top, refrigerator, and freezer, do not emit radiation in the same manner. A stove top generates heat through direct thermal conduction from flames or electric coils, while refrigerators and freezers use refrigeration cycles to remove heat but do not emit radiation to cook or heat food. Therefore, the microwave stands out as the only device in the options that relies on radiation to function.