challenge: What was the outcome of Muhammad II al-Mahdi's rule as the fourth Caliph of Córdoba?
  
  A. He established a period of peace and stability in Al-Andalus
  B. He expanded the Umayyad dynasty's territories in Iberia
  C. He was deposed after a turbulent rule marked by warring factions
  D. He successfully defended his title against all opposition
  Answer: 