Final answer:
Statement A is correct because white walls reflect visible light but do not emit it. Statement D is also correct to some extent because white walls can absorb and emit infrared radiation, albeit less efficiently than darker colors. Statements B and C are incorrect.
Step-by-step explanation:
The white walls in your room reflect visible light but they do not emit visible light. When white light (which contains all the colors of the spectrum) falls on a white surface, the surface reflects most of that light, which is why the walls appear white. Since the walls themselves are not a light source, they do not emit visible light. Therefore, statement A is correct: The white walls in your room reflect visible light but they do not emit visible light.
White objects, including your walls, may absorb and emit infrared radiation, which is a form of heat. While it's true that white is a poor absorber and radiator of heat, this does not mean that white walls do not absorb or emit any infrared radiation at all. It's simply that they do it less efficiently than darker colors. So, statement D could also be considered correct: The white walls in your room absorb and emit infrared radiation.
Statements B and C are incorrect because white walls do not emit visible light and the fact that white walls reflect light does not mean they also emit it. Visible light emission would imply that the object is a light source, which typical walls are not.