In a Buyer-Seller Relationship,reciprocity Refers to

In a buyer-seller relationship,reciprocity refers to

A) the practice whereby a seller requires the purchaser of one product to buy another item in the line.
B) an industrial buying practice in which two organizations,in this case a manufacturer and a supplier,agree to purchase each other's products and services.
C) an arrangement a manufacturer makes with a reseller to only handle its products and not those of competitors.
D) the illegal practice of refusing to purchase a seller's products unless the seller agrees not to purchase that product or any similar products from any other buyer.
E) when a supplier requires a buyer purchasing some of its products to also buy others.