The correct answer is C. The Crusades.
Step-by-step explanation
The fragment is a religious appeal by Pope Urban II to the Council of Clemont about the Muslim and Turkish invasions of the territory of the Byzantine Empire that was affecting the Christian Church. In this appeal, the Pope alarms about the situation in the Middle East by saying "Your brethren who live in the Middle East are in urgent need of your help ... For, as most of you have heard, the Turks and the Arabs have attacked them and have conquered the territory of Romans (the byzantine empire) ...". Later on, he refers to the call he makes to form an army and prevent the Arabs and Turks from continuing to gain more influence in the Middle East by saying that "All who die by the way, whether by land or sea, or in battle against the pagans, shall have immediate remission of sins".
This call is part of the Crusades, the religious wars promoted by the Catholic Church to recover for Christianity the region of the Middle East where the Byzantine Empire was located.
Therefore, the correct answer is C. The Crusades.