What is supplier power?

Select one:

a$.$ high when there are many alternatives to a product or service and low when there are few alternatives from which to choose

b$.$ the suppliers' ability to influence the prices they charge for supplies $($including materials, labor, and services$)$

c$.$ high when it is easy for new competitors to enter a market and low when there are significant entry barriers to joining a market

d$.$ the ability of buyers to affect the price they must pay for an item