Which organisms are most closely related A.Anas cyanoptera and Mycteria americana B.Martes americana and Mycteria americana C.Anas discors and Anas americana D.Aix sponsa and Anas acuta?

The organisms most closely related are C. Anas discors and Anas americana, as they both belong to the genus Anas and share a more recent common ancestor compared to the other pairs. In contrast, the other pairs consist of organisms from different genera or families, indicating a greater evolutionary distance.