The marketers of Bolthouse Farms spent a week sampling their products at fitness centers, health food stores, and grocery stores. At end of the week, Bolthouse Farms compared its sales figures against the figures of the previous week when it did not offer a free sample special. This scenario depicts how Bolthouse Farms measured the success of a$($n$)$

Multiple Choice

sales promotion.

advertising campaign.

public relations campaign.

personal selling efforts.

direct marketing campaign.