How Does a Facilitative Relationship Create Value for Both Buyer

How does a facilitative relationship create value for both buyer and seller?

A) The buyer trusts that the seller will deliver the product and the seller trusts that the buyer will pay for the product.
B) The buyer increases costs by buying from one seller,and the seller decreases profits by selling to the same buyer.
C) The buyer saves time and money by using only one seller,and the seller reduces buying and marketing costs by repeat sales to the same buyer.
D) The buyer saves money by limiting the number of presentations it listens to,and the seller saves money by reducing the shipping costs it charges the buyer.
E) The buyer reduces costs by eliminating the buying center,and the seller reduces the sunk costs of developing elaborate sales presentations.