Which of the following is NOT one of the four forces that ushered in the era of relationship marketing:

Marketing academicians and researchers began to point out the need for companies not only to acquire new customers but also to continue to market to current customers.

Direct marketing continued to grow through $800$ numbers and credit cards.

Advances in IT made relationship marketing feasible.

Marketers began shifting focus from maintenance, enhancement, and retention of customers to acquisition of new customers.

Many influential articles were written in the $90$s showing that companies with the highest retention rates earned the best profits.