Which of the Following Statements BEST Defines Direct Marketing

Which of the following statements BEST defines direct marketing?

A) another term for telemarketing or telesales
B) any approach that permits customers to place orders by telephone, Internet or post
C) an interactive system of marketing that uses one or more advertising media and results in a measurable response
D) any approach used by an organisation that leads to a sale
E) marketing activities conducted via telephone or over the Internet