Which One of the Following Is Not a Factor That

Which one of the following is not a factor that affects the strength of supplier bargaining power?

A) whether needed inputs are in short or ample supply
B) whether industry members are a strong threat to integrate backward into the business of suppliers
C) whether industry members are struggling to make good profits because of slow-growing market demand
D) whether the costs of industry members to switch their purchases to alternative suppliers or substitutes are high or low
E) whether the item being supplied is a commodity that is readily available from many suppliers