What is the first step when constructing an angle bisector using only a compass and a straightedge?

A. Place the compass needle on one of the legs of the angle, and draw an arc intersecting the other leg.
B. Place the compass needle on the vertex of the angle, and draw an arc across both legs of the angle.
C. Mark a point outside the angle, and draw an arc centered at the point, intersecting the vertex of the angle.
D. Mark a point outside the angle, and draw a ray in any direction from the point.
E. Mark a point in the angle's interior, and draw an arc centered at the point, intersecting both legs of the angle.