Which of the Following Factors Is NOT a Relevant Consideration

Which of the following factors is NOT a relevant consideration in judging whether buyer bargaining power is relatively strong or relatively weak?

A) Whether certain customers offer sellers important market exposure or prestige
B) Whether customers are relatively well-informed about sellers' products,prices,and costs
C) Whether buyer needs and expectations are changing rapidly or slowly
D) Whether sellers' products are highly differentiated,making it troublesome or costly for buyers to switch to competing brands or to substitute products
E) Whether sellers pose little threat of forward integration into the product market of their customers and whether buyers pose a major threat to integrate backward into the product market of sellers