Secret Sneaker Will Give Anyone $10 for an Old Pair

Multiple Choice

Secret Sneaker will give anyone $10 for an old pair of sneakers,regardless of condition,when that person purchases a new pair of sneakers.The end result is essentially reducing the price of the new sneakers by $10.What is this type of price adjustment called?

A) functional discount
B) by- product
C) captive product
D) seasonal discount
E) trade- in allowance