The correct answer is D) They measure distance east and west of the Prime Meridian.
The statement accurately describes lines of longitude on a map is "They measure distance east and west of the prime meridian."
Longitude is the vertical mapping lines. These are called meridians. The lines are a numerical way to find a location east or west from the Primer Meridian. This is a line that runs North to South, over the observatory in Greenwich, Great Britain. The other lines are called parallel, and they measure the distance North and South of the Equator.