Answer: A) It sets up a contrast between "To err" and "to forgive" and B) It helps the speaker emphasize the idea of forgiveness.
Explanation: In poetry, a caesura is a pause in a line that is formed by the rhythms of natural speech rather than meter. A caesura will usually occur in the middle of a line of poetry but can occur at the beginning or the end of a line. In the given excerpt the use of the caesura in the last line, shows contrast between to err and to forgive and it helps the speaker emphasize the idea of forgiveness.