Although Some Economists Believe Network Externalities Are Important Barriers to Entry

Multiple Choice

Although some economists believe network externalities are important barriers to entry, other economists disagree because

A) they believe that the dominant positions of firms that are supposedly due to network externalities are to a greater extent the result of the efficiency of firms in offering products that satisfy consumer preferences.
B) they believe that most examples of network externalities are really barriers to entry caused by the control of a key resource.
C) network externalities are really negative externalities.
D) they believe that the dominant positions of firms that are supposedly due to network externalities are to a greater extent the result of economies of scale.