Answer:
C. construction of a perpendicular to a line through a given external point
Step-by-step explanation:
The crossing arcs below the line are equidistant from the marked points on the line (J and K), and those are equidistant from point A. If we call the point of intersection of those crossing arcs point X, we know that AX is a perpendicular bisector of JK.
However, J and K are not part of the "given" of this construction. Rather, they are the result of the first step of drawing arcs centered at A. So the fact that AX bisects JK is not important. What is important is that AX is perpendicular to the line and goes through the given point A.
This is a partially-completed construction of a perpendicular to a line through the given external point A.
