Concept:The compilation of the Qurʼan into a single book was initiated during Abu Bakr's caliphate, based on a suggestion by Umar ibn al-Khattab.
Explanation:After the death of Prophet Muhammad (peace be upon him), many companions who had memorized the Qurʼan died in battle.
Abu Bakr became concerned that parts of the Qurʼan could be lost if the remaining memorizers also died.
Umar ibn al-Khattab advised Abu Bakr to have the Qurʼan collected and written down in one volume.
Abu Bakr accepted this advice and entrusted Zayd ibn Thabit, a trusted scribe of revelation, with the task.
Zayd collected written fragments and verified them against the memorization of the companions.
Later, during Uthman ibn Affan's rule, the compiled text was standardized into one official version.
Therefore, the initial compilation was made on the advice of Umar ibn al-Khattab.
Answer:D. Umar bn Khattab