Question

olena started constructing a perpendicular bisector for line segment $overline{ab}$. her progress is shown. olena lost her compass. can she finish constructing the perpendicular bisector? explain

no because a compass is necessary to draw two more arcs below the line segment
no because a compass is necessary to measure the length of the perpendicular bisector
yes because the only step left is to draw a line that passes through the intersection of the arcs and line $ab$ which olena can accomplish with a straightedge
yes because the only step left is to draw a line that passes through the intersection of the arcs and is perpendicular to line $ab$ which olena can accomplish with a straightedge

Explanation:

To construct a perpendicular bisector of a line - segment, after drawing arcs from both endpoints above the line - segment, the next step is to draw a straight line through the intersection of these arcs and the line - segment. This can be done with a straightedge. A compass is not needed for this final step.

Answer:

Yes, because the only step left is to draw a line that passes through the intersection of the arcs and line $AB$ which Olena can accomplish with a straightedge.