PerfectSweatShirt Company Makes and Sells a High-End Hoodie Sweatshirt Through

PerfectSweatShirt Company makes and sells a high-end hoodie sweatshirt through an online website.After a recent order,Jane received a discount code she could give to a friend.She sent the code to her friend Amy,and when Amy used the discount code,Jane received a five-dollar credit on a future purchase.PerfectSweatShirt is using a(n)

A) product promotion activity.
B) owned media system.
C) viral management technique.
D) referral program.
E) advertising allowance.