49)John signed a two year contract with AT&T to get a reduced price on his new iphone. He has had AT&T service for only 6 months and has been dissatisfied with AT&T service so he would like to switch to Verizon. However, cancelling his AT&T contract will cost him $250. Which of the following characteristics of a powerful supplier group does AT&T have with respect to their contract with John?
(A)The supplier industry is more concentration than the industry it sells to
(B)Industry participants face switching costs in changing suppliers
(C)Suppliers offer differentiated products
(D)No substitutes exist for what the supplier group provides