Question

30. Trisha wants to create the perpendicular bisector of a line segments

Answer 1

The answer is D:

Place the compass on point B and complete the same steps that she did for point A

The process is that you draw arcs above and below the line from both ends, but it's crucial that the compass' radius is the same from both ends of the line.  Then you draw the line that connects the two intersection points to form your perpendicular bisector.