Starbucks Sometimes Offers a Promotion Known as the "Treat Receipt

Starbucks sometimes offers a promotion known as the "treat receipt." Patrons purchase a drink of their choice in the morning and then will receive a receipt to turn in after 2:00 p.m. that same day. With the receipt the customer can purchase a discounted grande iced beverage. Which is the most likely market modification strategy for Starbucks here?

A) finding new users
B) creating new use situations
C) increasing a product's use by existing customers
D) modifying the product
E) reacting to competitors' positions