Final answer:
The promotion described in the question is an example of sales promotion, where a cereal company places certificates for a cash prize in selected boxes to encourage consumers to purchase their product.
Step-by-step explanation:
The promotion described in the question, where a cereal company places certificates for a cash prize in selected boxes, is an example of sales promotion.
Sales promotion is a marketing strategy aimed at increasing sales or creating awareness about a product or service. In this case, the company is using the cash prize certificates as an incentive to encourage consumers to purchase their cereal.