Answer: C) I love thee freely, as men strive for right.
Step-by-step explanation: A simile is a figure of speech that consists in making a comparison between elements that aren't obviously related, this comparison is made by using the words "like" or "as." In the given lines of the poem "Sonnet 43" by Elizabeth Barrett Browning we can see an example of simile in the phrase " I love thee freely, as men strive for right" here she is comparing her love to men striving for right (which is the pursuit of a social cause).