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 the number of buyers is small or if a customer is particularly important to the seller
B) Whether buyers are relatively well informed about sellers' products,prices,and costs
C) Whether buyer needs and expectations are changing rapidly or slowly
D) Whether buyer demand is weak or strong and rapidly growing
E) Whether buyers pose a credible threat of integrating backward into the business of sellers