Concept:The Mahdiyya Movement fought to end foreign control, and its forces decisively defeated the British-Egyptian army at the fall of Khartoum.Explanation:The Mahdists, led by Muhammad Ahmad, captured Khartoum in 1885.General Gordon and the British-Egyptian garrison were killed during this siege.This defeat marked the climax of Mahdist success against British-Egyptian rule.The other options refer to later battles where the British ultimately conquered the Mahdist state.Answer:C. Khartoum