Which of the following is a form of sales promotion?

The form of sales promotion from the given options is "Offering free samples to customers". Sales promotion refers to the marketing activities other than advertising, personal selling, and public relations, aimed at stimulating consumer purchases and dealer effectiveness. Offering free samples to customers is a common form of sales promotion where companies distribute free samples of their products to customers. This allows customers to try out the product without any obligation to buy and can help to increase sales by generating interest and familiarity with the product.