Winner
Diverse in Unity
I was given to believe that the North Sea is part of the Atlantic Ocean, at least technically. Also, you forgot Germany.
Germany suffered a lot because its access to open oceans was dependent on a free movement through the North Sea and the Channel. Once these two routes were blocked by the English navy in WW1, German maritime trade was utterly ruined.
Austria-Hungary was in far worse position, since the Straits of Taranto is much, much easier to block and the Italians hardly had any difficulty keeping the A-H navy at bay during WW1.