Because we care so much for the health of our customers, our natural spring water comes from pure springs that we maintain to the utmost standards. all of our water is tested for sediment and calcium, which we filter out through a reverse osmosis process in our bottling plants. then we conduct a strict comprehensive process utilizing a multi-barrier system to ensure the quality that our customers have come to expect from deer river water. 6 this passage was taken from the public relations section of the deer river water bottling company's web site. how does the author's motivation affect the credibility of the writing? a. the author is a consumer giving a testimonial, so the writing is completely trustworthy and credible. b. the author does not have any particular motive, so there is no reason not to believe the claims made in the ad. c. the author is clearly an expert on the subject of bottled water, so the writing is completely credible. d. the author is trying to sell something, so the writing is biased in favor of the product.