In $2014,$ McDonald$$s in Sweden started accepting empty aluminum cans as payment. To buy a hamburger or a cheeseburger, customers could pay with $10$ cans. A Big Mac costed $40$ cans. McDonald$$s would then exchange the cans for cash at the recycling depot.

By implementing this policy, which of the circular economy building blocks did McDonald$$s stimulate the most?

Group of answer choices

Product as service.

Reverse logistics$.$

Product life extension.

Design.