3. Which of the following is most likely an observation of the Doppler effect that led to the discovery that the Universe is expanding?
a. When observed from a black hole, all of the stars in the Universe have
blueshifts.
b. The spectra of light given off by stars in the Milky Way Galaxy have
blueshifts,
c. When observed from Earth, light spectra from stars in other galaxies
have redshifts
d. The spectrum of light given off by the Sun has a redshift when it is
observed from Earth,