Concept:The Gezira irrigation scheme in Sudan uses some Nile dams, but not all of them.Explanation:The main dams used in the Gezira scheme are the Sennar Dam and the Roseires Dam.The Jebel Azula dam is not part of the Gezira scheme.So the dam that is not used in the Gezira is Jebel Azula.Answer:D. Jebel Azula