One important measure of social media's effectiveness is the percentage of site visitors who take the action the site owner hoped for—making a purchase, subscribing to a service, or donating money, for example. This measure is called the site's:

the answer is b. executive summary. a management summary, or executive summary, is a short article or section of a document, produced for business purposes, that condenses a longer report or proposal or a group of related reports in such a way that readers can rapidly become familiar with a large body of material without having to read it all.