Who gave Hazrat Abu Bakr (R.A) the idea to compile the Quran in the form of a book? 

1. Hazrat Salman Farsi
2. Hazrat Umar (R.A.)
3. Hazrat Khalid Bin Waleed
4. Hazrat Usman (R.A.)

After Yamama’s battle (633 CE), Hazrat Umar (R.A.) urged Abu Bakr (R.A.) to compile the Quran, fearing huffaz’s deaths. Initially hesitant, Abu Bakr later approved, as per Sahih Bukhari (Book 93, Hadith 53). This became the Suhufi Siddiqi, later expanded by Usman (R.A.).