Final answer:
Burger King is offering a premium sales promotion by including a free backpack with the purchase of a luxury meal pack to entice customers.
Step-by-step explanation:
Burger King is implementing a sales promotion by offering an official Burger King Kids' Meal backpack with the purchase of its newly introduced luxury meal pack. This type of promotion can be classified as a premium. A premium is a promotional strategy where a bonus item is included with the purchase of a product, often used to entice customers to buy a specific product.