In which relationship stage does ?grave dressing? occur?

Manuel conducted a study in a local high school about the effectiveness of humor in a television anti-smoking campaign. After the study was over, he discovered that a popular musician had died of lung cancer during the course of the campaign, and many students stopped smoking in her honor. This is an example of:

a. A problem with external validity b. A problem with internal validity c. A history effect d. Both a problem with internal validity and a history effect

Informative and persuasive speeches do not require facts and expert opinions

Indicate whether the statement is true or false.