The correct answer is D) God will reward those who liberate Jerusalem.
The best statement that summarizes what the pope is saying is "God will reward those who liberate Jerusalem."
During the Crusades, the Byzantine emperor requested help from the pope to protect, defend, and control the Holy Land.
Both Christians and Muslims wanted to control the holy land of Jerusalem. This derived in the Crusades War. Eight major crusades confrontation happened from 1096 to 1291. The Middle Ages were times of conflict and wars. The Muslims had attacked Byzantine Empire territories and fought to secure the control of its sacred sites. The pope had to ask help from other Western European nations to fight the powerful Muslim army.