To determine if line segment \( \overline{NO} \) is a constructed copy of line segment \( \overline{PQ} \), Thuy must measure the length of \( \overline{PQ} \) and compare it to \( \overline{NO} \). The most appropriate approach would be:
"She must measure the distance from point O to point Q using a compass and place the compass on point P to see if point N is the same distance."
This option correctly describes the process of using a compass to copy the length of \( \overline{PQ} \) to see if \( \overline{NO} \) is congruent to \( \overline{PQ} \).