Two prominent lines in the laboratory emission spectrum of hydrogen are observed at 434 nm434\text{ nm}434 nm and 486 nm486\text{ nm}486 nm. A stellar spectrometer is configured to record spectra over the wavelength range from 440 nm440\text{ nm}440 nm to 500 nm500\text{ nm}500 nm.
An absorption spectrum of this same wavelength range is obtained from Earth for light from a distant galaxy that is approaching us at a velocity of 0.050c0.050c0.050c.
Which of the following describes the lines visible in this observed absorption spectrum within the spectrometer's range?
Dark lines at 412 nm412\text{ nm}412 nm and 462 nm462\text{ nm}462 nm on a bright background
A single dark line at 462 nm462\text{ nm}462 nm on a bright background
A single bright line at 462 nm462\text{ nm}462 nm on a dark background
A single dark line at 456 nm456\text{ nm}456 nm on a bright background
