Who was first preacher of Islam appointed by Hazrat Muhammad (SAW) for the people of Madina...? Mcqs

Who was first preacher of Islam appointed by Hazrat Muhammad (SAW) for the people of Madina...?

(A) Hazrat Musab ibn Umair (RA)

(B) Hazrat Jafar Tayyar (RA)

(C) Hazrat Ayub Ansari (RA)

(D) Hazrat Usman (RA)