To try to help Americans prepare for a terrorist attack, the U.S. Department of Homeland Security used a new $10.2 million advertising campaign involving both print and broadcast media. Prior to the development of the advertisements, the department conducted concept tests with small groups of eight to ten average U.S. citizens from New York City, Kansas City, Los Angeles and elsewhere who gave their opinions on what the ads should contain and how the message should be delivered. This is an example of:

post-testing through focus groups

field testing through the use of single-source data

pretesting through focus groups

the Delphi method of testing advertising effectiveness

a physiological assessment method