Question

what type of construction do you see? perpendicular bisector angle bisector altitude midpoint

Explanation:

The diagram shows a line with another line crossing it at a right angle (perpendicular) and also bisecting the original line (as indicated by the markings and the crosses, which are typical for constructing a perpendicular bisector). An angle bisector is for angles, altitude is related to triangles, and midpoint is just a point, not a construction. So the construction is a perpendicular bisector.

Answer:

A. perpendicular bisector