Answer:
The advertising technique that involves the giving of an additional item at no extra cost is:
Explanation:
Promotion is an advertising technique based on the customer's perception regarding the price or service provided for a good or service, when an additional item is offered at no extra cost, the customer immediately assumes that the product they are buying has a lower value than others of the same style since you are carrying an additional product with which, if the price were divided between the two products, you would notice a profit.
