In Which of the Following Circumstances Are Competitive Pressures Associated

In which of the following circumstances are competitive pressures associated with the bargaining power of buyers not relatively strong?

A) when buyer demand is growing rapidly
B) when buyers are relatively well informed about sellers' products,prices,and costs
C) when buyers pose a major threat to integrate backward into the product market of sellers
D) when sellers' products are weakly differentiated,making it easy for buyers to switch to competing brands
E) when buyers have considerable discretion over whether and when they purchase the product