I need help choosing an object

Photoshop has got amazinly good at this sort of problem recently.  Use the Remove Tool and paint over the curtain cord

If you are happy with that, then leavew as it is.

If you want to recreate the chord then select the Brush tool, with a small round, fully hard, preset, and adjust the spacing in Brush Settings (F5)

Create a new layer, and stamp the brush at the top of the chord position.

Then hold down the Shift key and stamp down at the other end of the chord.

I used a dark grey, and reduced the layer opacity a tiny bit to make it look more real.  You can use any colour you like.

If the spacing is wrong, undo it (Ctrl Z) readjust spacing and try again.

I would try to match the cord with a curve/shape made with the pen tool, add a round dotted stroke and play around with the settings to sort of match it, then rasterize and use that as a selection for the mask. Other selection methods will vary in efficiency depending on the resolution, scale and detail around the areas.