When a star moves toward or away from the earth, the light will be in a slightly different place in the spectrum from where a start would be at rest.
Due to the doppler effect, if a star moves toward the earth, the star's spectral lines will make a shift toward the blue end of the spectrum.
Therefore, the light waves from a star as the star moves toward the earth will appear to shift toward blue.
ANSWER:
B. They appear to shift toward blue.
