The answer to this would be B- Longitudinal Study.
Answer:
The Hijra, or the relocation of Muhammad and his followers from Mecca to Medina, was important because it allowed Islam to establish a community, or umma. Whereas Muslims faced persecution from the polytheistic majority in Mecca, the people of Medina accepted Islam and used religious unity to overcome clan rivalries.
Mary Beard is a historian currently studying ancient Rome.
Joe McConnell is a professor currently studying rome.
Not sure if this is what you meant, but i hope it helps