Partypolist, a Store That Sells Party Supplies, Sends Discount Coupons

Multiple Choice

Partypolist, a store that sells party supplies, sends discount coupons to its regular customers before Christmas and Halloween every year. In the context of the evolution of marketing, which of the following eras does this scenario most likely refer to?

A) The selling era
B) The production era
C) The relationship era
D) The marketing era