Concept:The Sokoto Caliphate included territories conquered during the 19th-century Fulani jihad in northern Nigeria.Explanation:Kukawa was a capital of the Kanem-Bornu Empire, not Sokoto.Biu was associated with the Biu kingdom, outside the Sokoto Caliphate.Lokoja was a later British administrative settlement at the Niger-Benue confluence.Yauri, a Hausa kingdom along the Niger River, was conquered and incorporated into the Sokoto Caliphate.Answer:Yauri.