The colorful patterns observed on a compact disc (CD) in sunlight are due to the phenomena of reflection and diffraction. CDs have closely spaced tracks that act as a diffraction grating. When sunlight strikes the disc, the light reflects off the shiny surface and the grooves cause the light to diffract. This diffraction separates the light into its component colors, creating a spectrum similar to a rainbow. The combination of reflection from the disc’s surface and the interference of light waves due to diffraction leads to the vibrant colors. Thus, the correct explanation involves both reflection and diffraction (Option A). The intricately patterned surface of the CD enhances this effect, making the colors more pronounced and visible from different angles.