Final answer:
Yathrib is correctly identified as Medina, a city of historical importance as the destination of Prophet Muhammad's Hijra in 622 CE, which is marked as the starting point of the Islamic calendar.
Step-by-step explanation:
The correct letter that identifies Yathrib, later renamed Medina, on historical maps would be the one associated with its location approximately 200 miles north of Mecca. Yathrib, known today as Medina or Medina (the city of the Prophet), holds great significance in Islamic history as the destination of Muhammad's Hejira (Hijra) in 622 CE. This momentous event marked the beginning of the Islamic calendar and was pivotal in the establishment of Islam as a community and a religion.
The Hijra, meaning 'emigration', was not just a physical journey but a crucial turning point for the early Muslim community. Muhammad's migration was invited by the people of Medina who sought his leadership and mediation. This shift towards a unified community under Muhammad's guidance allowed Islam to grow beyond its initial confines in Mecca and become a significant presence in world history.