A) Hazrat Abu Ubaidah bin Jarrah (RA)
B) Hazrat Muaz bin Jabal (RA)
C) Hazrat Zaid bin Sabit (RA)
D) Hazrat Abdur Rahman bin Auf (RA)
Correct Answer: A) Hazrat Abu Ubaidah bin Jarrah (RA)
Explanation: Hazrat Abu Ubaidah bin Jarrah (RA) was called Amin-ul-Ummat.