Sale promotion refers to any marketing activity that aims to stimulate customer demand and increase sales for a product or service. Out of the given options, the one that refers to sale promotion is "offering free samples of products."
This is because offering free samples of a product is a common sales promotion technique used by companies to encourage customers to try their products and potentially make a purchase in the future. By providing customers with a free sample, companies hope to create a positive experience with their product, generate word-of-mouth marketing, and increase the likelihood of future sales.
Non-personal presentation of a product refers to advertising, which is a separate marketing activity from sales promotion. Providing information about a company and its product can also refer to advertising or public relations. Direct contact with the ultimate buyer refers to personal selling, which is another type of marketing activity. Gathering information about a product refers to market research, which is not a sales promotion activity but rather a method used to inform marketing decisions.