Who gave the suggestion of digging the trench around the city of Madinah at the time of “battle of Khandaq”?

A. Abu Bakr Siddique (R.A)
B. Salman Al-Farsi (RA)
C. Khalid bin Waleed (R.A)
D. None of these

 Salman Al-Farsi (RA) gave the suggestion of digging the trench around the city of Madinah at the time of the “battle of Khandaq”.