Crowbar Records used to sell its music, in CDs, through a network of retail outlets, record stores, and music dealers. After the advent of MP3 technology, it decided to shift from using any of these agents and sell its music independently from the company's Web site, using personal mail, and other social networking techniques to inform potential customers about upcoming music and promotions. Which of the following types of marketing systems has Crowbar newly adopted? A. administered vertical marketing system
B. contractual vertical marketing system
C. horizontal marketing system
D. direct marketing channel
E. vertical marketing channel