Dear Editor: I feel obliged to comment on the unfair review you publis...
(A) Attacking the motives of the author of the unfavorable review: In the letter, the author accuses Mr. Duxbury of belittling their book in order to promote his own book. By questioning Mr. Duxbury's motives, the author is suggesting that the unfavorable review was biased and unfair. This method of argument attacks the credibility and integrity of the reviewer, rather than focusing on the content of the review itself.
(B) Attacking the book on the same topic written by the author of the review: The author does not directly attack the book written by Mr. Duxbury. Instead, they focus on Mr. Duxbury's motives and actions. While they mention that Mr. Duxbury published a book on the same topic, the letter does not provide any criticism or negative comments about his book.
(C) Contrasting her own book with that written by the author of the review: Although the author mentions that Mr. Duxbury published a book on the same topic, they do not explicitly compare or contrast their book with his. The letter does not provide any details or arguments about why the author's book is superior or different from Mr. Duxbury's.
(D) Questioning the judgment of the author of the unfavorable review: While the author indirectly questions the judgment of the author of the unfavorable review by accusing him of bias, the main focus is on Mr. Duxbury's motives rather than his judgment.
(E) Stating that her book should not have been reviewed by the author of a competing work: The letter does not explicitly state that her book should not have been reviewed by Mr. Duxbury or anyone with a competing work. The author's main concern is with Mr. Duxbury's alleged biased motives rather than the reviewer's eligibility.
Given these explanations, it is clear that the method of argument used in the letter is (A) Attacking the motives of the author of the unfavorable review.