Who was the Islamic caliph known for compiling the Quran into a single book?

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

Answer: Uthman ibn Affan


Additional Information: Uthman ibn Affan compiled the Quran into a single book during his caliphate.