On an episode of Greys Anatomy, an American television medical drama, one of the doctors asked a nurse for a Nitrolingual Pumpspray, which is used for acute relief of chest pain caused by angina. The free appearance of the product on the show gave its small manufacturer some needed publicity. This was an example of how _____ can result in positive publicity.

a. product placement

b. two-way communication

c. product advertising

d. product promotion

e. show sponsorship