<span>C. It is the difference in electrical potential energy between two places in an electric field.</span>
Bergeron–Findeisen Process.
Astronomers can measure a star's position once, and then again 6 months later and calculate the apparent change in position. The star's apparent motion is called stellar parallax. The distance d is measured in parsecs and the parallax angle p is measured in arcseconds.
I hope this helps!
