Which of the Following Factors Is Not a Relevant Consideration

Which of the following factors is not a relevant consideration in determining the strength of buyer bargaining power?

A) Whether winning the business of prestigious customers gives a seller important market exposure and heightens its brand name
B) Whether the seller is a manufacturer.
C) Whether buyers pose a major threat to integrate backward into the product market of sellers
D) Whether sellers' products are weakly differentiated, making it easy for buyers to switch to competing brands
E) Whether collaborative partnerships and alliances between particular sellers and buyers put rivals lacking such collaborative relationships at a competitive disadvantage