B

Step 1: Understand the concept of a black body. A black body is an idealized physical object that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.
Step 2: As the temperature of a black body increases, it emits radiation across a range of wavelengths. According to Wien's Displacement Law, the wavelength corresponding to the peak emission of a black body shifts to shorter wavelengths as the temperature rises.
Step 3: At lower temperatures, black bodies emit more in the infrared or red spectrum; as the temperature increases, they emit more in the visible spectrum, first appearing red, then orange, and eventually white as the temperature rises significantly.
Step 4: At very high temperatures, a black body emits a significant portion of its radiation in the visible range, reaching a point where it emits all colors, resulting in a white appearance.
Therefore, at high temperatures, a black body appears white.