We “love the poet, the ________” because he unlocks our chains and admits us to a new scene.

The latter part of the sentence - “because _______ new scene” provides a clue for the blank. The poet unlocks our chains, i.e. he reveals a new scene, a new thought to us by his imagination. Therefore, he is an inventor of new thoughts, new emotions, and new expressions. Hence, (2) is the answer. “Librettist” is the writer of the words, or text of an opera or other long choral work. “Jongleur” is a wandering minstrel in medieval France and England, who entertained by reciting or singing.