In general, in the case of a regular polygon, the apothem is the perpendicular distance from the center to a side of the polygon, while the radius is the distance from the center to a vertex.
Therefore, in our case,
![\begin{gathered} apothem=a=OP \\ radius=r=OB,r=OA \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/80qv19yilwnj2hwshyghdqrctvcj1yj0yj.png)
Notice that two radii are drawn in the figure.
As for the perimeter of the 8-sided polygon,
![P=8(AB)](https://img.qammunity.org/2023/formulas/mathematics/college/t0jm0lxde7sbiltmbjedgwwa83b7c8aubn.png)
Thus, the answer is option D.