Which sentence blurs the focus of the second paragraph and should therefore be deleted?

Sentence 3 establishes that the focus of the second paragraph is on “Clifton’s enduring themes.” Sentence 4, which provides basic biographical information about Clifton, is not relevant at this point in the passage and should therefore be deleted.
The other choices are incorrect because sentences 5, 6, and 7 are all part of the same example illustrating an “enduring theme” of Clifton’s work and are therefore relevant to the focus of the second paragraph.