Whoops...well, the Catholic church gave us ALL of the gospels...without them we would have no idea at all of who Jesus was...the Jews certainly wouldn't have told us and there was no one else around. You can pick and choose which of the Gospels answers your questions, and if you can't figure it out from there, just consult ANY Catholic theologen because ONLY the Catholic church has the authority, FROM CHRIST, to interpret scripture....they wrote it, they interpret it...pretty simple when you think about it!!!
No it really isn’t “that simple”. Just because you believe that Christ died, was buried, and rose again the third day, that does not mean you believe the gospel that saves. It’s WHY He died that makes a difference in which “Christ” you believe in and follow for your salvation. As for “picking and choosing” which of the Gospels”, that would not be a very wise thing to do in this age of the grace of God. Paul says it is his gospel that God will use to judge the secrets of men by Christ. You’ll find this in Romans.