a. They are arcs drawn between the North and South poles
Explanation:
A longitude is a geographical coordinate that, measures the east and the west of the prime meridian and longitude is a considered to be an imaginary line and runs up and down vertically and connecting the two poles of north and south.
These lines are known as the meridians and they are expressed by the Greek letter as lambda and connect to the point n the same longitude. They are important form the cartographic and the navigation purpose.
