Business-To-Business Marketing Often Involves More of an Emphasis on Personal

Business-to-business marketing often involves more of an emphasis on personal selling than on advertising or other forms of promotion. Which of the following is the chief reason for this emphasis?

A) Personal selling is more cost-efficient than advertising.
B) Personal selling is more time-efficient than advertising.
C) Organizational buyers do not respond to advertising or promotions.
D) Organizational buyers typically require more face-to-face contact with sellers than end consumers do.