Several reasons.
Saw this crusade as a blessing from God.
Christians would stop fighting themselves.
Christians that would fight would go to heaven or be right with God.
To take back the holy lands, from the Muslims would be a righteous cause.
I think C) Roman Catholic; Eastern Orthodox is the answer but I'm not 100% sure. Hope this helped!!!
I don’t know if this is right but I am guessing Britain and France
