Easy-peasy time. The protagonist of David Copperfield is David Copperfield; the protagonist of Jane Eyre is Jane Eyre, and the protagonist of Adam Bede is (you guessed it) Adam Bede. Title character equals protagonist, when it comes to Victorian novels.
And although this is an ensemble cast, Adam Bede himself really is the star of the show. If The Sopranos had been titled Tony Soprano, no one would have batted an eye. Adam Bede is more about Adam's community than Adam himself, but Adam is the part that represents the whole here. Eliot's novel is about ordinary people doing (mostly good) ordinary stuff… and you don't get more ordinary—in an awesome way, of course—than our man Bede.