Why might the action of the seljuks in conquering southwest asia have ignited the christian crusades?

the greek christians had a falling out with the seljuks over trade policies.
the umayyads in spain were conspiring to overrun the seljuks with christian armies.
the seljuks conquests had cut off europe from access to jerusalem.
the christians of europe were offended by seljuk policies within byzantine lands.