Astarís light is shifted to the red part of the light spectrum.

what does this mean about the length of light waves and movement of the star?

a.
the wavelengths are getting shorter, meaning the star is moving toward the observer.

b.
the wavelengths are getting longer, meaning the star is moving toward the observer.

c.
the wavelengths are getting shorter, meaning the star is moving away from the observer.

d.
the wavelengths are getting longer, meaning the star is moving away from the observer.