Which member of Ashra Mubashara was given the title of Amin-ul-Ummat?

A. Hazrat Abu-Ubaidah Bin Al-Jirrah(RA)
B. Hazrat Saad Bin Abi Waqas(RA)
C. Hazrat Abdur Rehman Bin Auf(RA)
D. HAzrat Saeed Bin Zaid(RA)