Wal-Mart Stores Depend in Large Part on Their Suppliers to Monitor

Wal-Mart stores depend in large part on their suppliers to monitor Wal-Mart's inventory levels at their various distribution centers.When supplies of a particular product are diminished,it is up to the suppliers themselves to place reorders on behalf of Wal-Mart.This arrangement would reflect the cooperation found in _______________.

A) diagonal marketing system
B) traditional marketing system
C) horizontal marketing system
D) vertical marketing system