Why Is the Term  "Arc" Used to Describe Units of Measure

Multiple Choice

Why is the term  "arc" used to describe units of measure for angular distance?

A) To avoid confusion with the minutes and seconds of time
B) To describe the arc-shaped distance between the stars
C) To distinguish the base unit of 10 per degree
D) To distinguish the difference between northern and southern spheres
E) To describe the placement of the stars within each hemisphere