Which was a reason for the First Crusade?
a. Muslim caliphs wanted to overthrow the Jewish kingdom that had been established in Palestine.
b. European merchants wanted to establish trading outposts in Muslim territories of the Middle East.
c. When the Seljuk Turks took control of the Holy Land, it became more dangerous for Christians to travel there.
d. The pope called for the destruction of the Eastern Orthodox church at Constantinople.
"c. When the Seljuk Turks took control of the Holy Land, it became more dangerous for Christians to travel there" would be the best option, since most of the Crusades were largely about "taking back the Holy Land".
