Procter & Gamble, the maker of Crest brand toothpaste, has modified this brand to include whiteners. To encourage consumers to adopt this brand, P&G gave away free samples along with a high-value coupon on the purchase of a tube. The hope was that consumers would try the brand, purchase it at a discount, and finally buy it at full price. This is an example of _____.
A. step learningB. stagingC. steppingD. shapingE. modeling