The correct answer is:
C. I've known rivers.
Explanation:
Refrain in literature, is a technique where words, phrases or lines are repeated throughout a poem; they are often repeated at the end of each stanza, or at regular intervals. Refrain is also a common technique used in songs.
In the poem "The Negro Speaks of Rivers" written by Langston Hughes, the phrase I've known rivers appears at the beginning of the first two lines in the first stanza and almost at the end of the poem:
I’ve known rivers:
I’ve known rivers ancient as the world and older than the
flow of human blood in human veins.
....
I’ve known rivers:
Ancient, dusky rivers.