Final answer:
Option A correctly uses ellipses to integrate part of a quotation from Arnold, maintaining the sentence's context and grammatical integrity. Therefore, the correct option is A.
Step-by-step explanation:
The sentence which uses ellipses correctly when integrating the quotation is option A: Arnold writes that "the Sea . . . of Faith / Was once, too, at the full." The ellipses indicate that some text has been omitted, but the context and grammatical structure of the sentence remain intact. This use of ellipses helps to integrate the quotation smoothly into the text without altering its original meaning or structure.