Final answer:
A star getting closer results in a blue-shift with shorter wavelengths, while a star moving away will show a redshift with longer wavelengths.
Step-by-step explanation:
The student's question appears to have a slight mistake in its description of redshift. In fact, if a star is getting closer, the spectra will not be red-shifted but instead blue-shifted, where the spectral lines move towards the blue end of the visible spectrum. Therefore, the correct answer for a star moving closer is that the wavelengths will be shorter, not longer. Redshift occurs when the source of light is moving away from the observer, which results in the spectral lines being displaced toward longer wavelengths (toward the red end of the spectrum).