Which sentence contains the correct homophone?

Edward has been sitting idyl since morning.

Edward has been sitting idol since morning.

Edward has been sitting idle since morning.

Edward has been sitting idyll since morning.

Answer: Edward has been sitting idle since morning.

That sentence means that Edward has sitting and inactive, doing nothing, since the morning.

Check the other homophones at a dictionary and you will realize that they cannot form a logical sentence in the way they are being used here.