Who was the first caliph to standardize the Quranic text?

A. Abu Bakr al-Siddiq
B. Ali ibn Abi Talib
C. Umar ibn al-Khattab
D. Uthman ibn Affan

Answer: Uthman ibn Affan


Additional Information: Uthman ibn Affan standardized the Quranic text to avoid variations and distributed copies to different regions.