D the fashion now is to have a drapery rod floating somewhere above the actual window but I like t hem at the top of the trim. The upper windows were not ment to be covered.

Do you need the curtains to fully close or are they just decorative?

If just decorative, we typically install in the "B" range of your photo and we frequently use a short rod on each side instead of a solid rod going all the way across.

For panels, I would do from the D line only because of those upper windows.

I would also think about solar shades instead. Or both. That way the panels can stay open.

Lovely home and view! My preference is to not block the view.

I was thinking about D and keeping the top open

Take the rod above the upper window as TraVerse Enterprises advised (level B). Short rods on either side or one rod over the entire opening will work. Your choice. However placing the rod between the upper and lower windows will make the windows look short and squatty. You’ll literally ruin the beauty and wow factor of having this large wall of windows. What is the top of window to floor measurement for that lower window? It looks very low. Do not place the rod at level C or D.

How about a subtle accent to the whole wall…painting it a pretty pale color?..no curtains…adding rugs and pillows with the same color to keep the interest down at “people level”…with all that natural light …some pretty plants should flourish in this room as well

The plant on the left is a perfect size…but in this setting symmetrical plants will be more suitable

I stand firm on my choice. I wouldn't have a problem with TraVerse’s idea, it is fine all the time, but.,,,,.you have an arched window and that makes the difference.

I see it as a complete design feature and it seems odd to cover part of it.