An ellipsis is used incorrectly in sentence D, "Abigail confessed that she..."loved the novel by Jane Austen more than the novel by Mark Twain."
An ellipsis (or three dots) is used to delete unimportant information. In sentence D the elipsis is not necessary because the speaker is not eliminating anything from the quote. In options A and C, the ellipsis is at the end, symbolizing that there is more to the quote than what is written. Also, in option B, the speaker is eliminating the first names of the author. While the sentence would be fine without the ellipsis, it is not incorrect.