Which of the Following Statements About a Vertical Marketing System

Which of the following statements about a vertical marketing system (VMS) is true?

A) The three types of VMS are independent,conventional,and customized.
B) Conventional marketing systems are more efficient than vertical marketing systems.
C) Channel conflict is a serious problem that erodes efficiencies in many vertical marketing systems.
D) Members of a VMS operate totally independently of one another outside of buying and selling one another's products.
E) A VMS is a channel in which there is cooperation among channel members at two or more different levels of the channel.