An e-commerce revenue model where the seller has control over pricing but doesn't keep products in stock and instead transfers customer orders and shipment details to a third-party supplier, who then ships the goods directly to the customer, is called:

1. A

   Dropshipping Model

   Dropshipping Model. This is a retail fulfillment method where the store doesn't keep the products it sells in stock. Instead, when a store sells a product, it purchases the item from a third party and has it shipped directly to the customer, retaining control over the final retail price.

2. B

   Affiliate Revenue Model

   Affiliate Revenue Model. This involves a business directing traffic or sales to an external website in exchange for a commission on the resulting transactions, rather than fulfilling orders or managing inventory itself.

3. C

   Transaction Fee Revenue Model

   Transaction Fee Revenue Model. This model involves a company charging a fee for enabling or executing a transaction between two other parties, such as payment gateways or digital marketplaces acting as intermediaries.

4. D

   Agency Revenue Model

   Agency Revenue Model. In this model, an agent or intermediary acts on behalf of a principal to facilitate a transaction, typically earning a commission or percentage of the sale while the principal retains ownership and pricing control.

Summary. Official key is (a). The dropshipping model precisely defines a retail setup where the seller controls pricing without holding physical inventory, relying instead on a third-party supplier for direct shipment. The other options describe different digital business models—such as commissions for referrals, transaction fees for facilitation, or agency commissions—none of which match this specific inventory-less fulfillment arrangement.