In Which of the Following Is the Option Described Not

In which of the following is the option described not a performance obligation?

A) Customers accumulate points for every dollar spent at Madeline's Book Store.The points can be redeemed for books once certain levels are met.
B) Customers can get 5% cash back for every $100 spent on eco-friendly products.
C) Customers can "buy two,get one free" at a menswear store.
D) Upon purchase of any name-brand TV,customers can purchase a 5-year extended warranty at a 25% discount.