Which sales strategy involves offering customers additional related products?

The sales strategy that involves offering customers additional related products is known as cross-selling. This approach encourages customers to consider complementary items that enhance or relate to their original purchase. For example, if a customer orders a burger, the server might suggest adding fries or a drink, thereby increasing the overall sale amount while enhancing the customer's experience.

Up-selling, which was selected as the answer, typically focuses on encouraging customers to purchase a more expensive item or an upgrade instead of additional products. For instance, a server might suggest a premium steak instead of a standard one or a larger size of a beverage. While this strategy also aims to increase sales, it does not necessarily involve related products, but rather an upgrade of a similar product.

Bundling refers to offering multiple products together at a lower price compared to purchasing them separately. Discounting involves reducing the price of an item to stimulate sales. These strategies serve different purposes and would not specifically fit the description of providing additional, related products in the context of sales techniques.