Which transportation network design option establishes an extra layer between suppliers and retailers to store inventory and to serve as a transfer location?

A) Direct shipping network
B) Direct shipping with milk runs
C) All shipments via central DC
D) Direct shipping

The option of shipping all products via a central distribution center would establish an extra layer between suppliers and retailers, as the products would be stored in the central DC before being distributed to the retail locations. This would provide an opportunity for inventory to be maintained at the DC and allow for more efficient transfer of products to the retailers. The other options do not establish an extra layer between suppliers and retailers, as they involve direct shipping from suppliers to retailers without any intermediary storage or transfer locations.