Since the shape of the frame is a square we know that its area is given as:

where l is the length of each side, plugging the value of the area into the equation and solving for l we have:
![\begin{gathered} 123=l^2 \\ l=\sqrt[]{123} \\ l\approx11.09 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/1iw2pjgtwfv8lvw1lff9adjl5mej9lpn11.png)
Therefore we notice that the length of the sides is between 11 and 12 inches, hence the answer is C.