People who receive unsolicited advice from someone whose

People who receive unsolicited advice from someone whose advantage would be served if that advice is taken should regard the proffered advice with skepticism unless there is good reason to think that their interests substantially coincide with those of the advice giver in the circumstance in question.

This principle, if accepted, would justify which one of the following judgments?

(A) After learning by chance that Harriet is looking for a secure investment for her retirement savings, Floyd writes to her recommending the R&M Company as an especially secure investment. But since Floyd is the sole owner of R&M, Harrier should reject his advice out of hand and invest the savings elsewhere.
(B) While shopping for a refrigerator, Ramon is approached by a salesperson who, on the basis of her personal experience, warns him against the least expensive model. However, the salesperson’s commission increases with the price of the refrigerator sold, so Ramon should not reject the least expensive model on the salesperson’s advice alone.
(C) Mario wants to bring pastry to Yvette’s party, and when he consults her Yvette suggests that he bring his favorite chocolate fudge brownies from the local bakery. However, since Yvette also prefers those brownies to any other pastry, Mario would be wise to check with others before following her recommendation.
(D) Sara overhears Ron talking about a course he will be teaching and interrupts to recommend a textbook for his course. However, even though Sara and Ron each wrote a chapter of’ this textbook, since the book’s editor is a personal friend of Sara’s, Ron should investigate further before deciding whether it is the best textbook for his course.
(E) Mel is buying fish for soup. Joel, who owns the fish market where Mel is a regular and valued customer, suggests a much less expensive fish than the fish Mel herself prefers. Since if Mel follows Joel’s advice, Joel will make less profit on the sale than he would have otherwise, Mel should follow his recommendation.