Research on public service ads designed to promote healthy behavior indicates that such efforts  a. almost always fail. b. are more effective at changing the attitudes of men versus women. c. are more...

Research on public service ads designed to promote healthy behavior indicates that such efforts

 a. almost always fail.

b. are more effective at changing the attitudes of men versus women.

c. are more effective via television than print ads when their target is young people.

d. are most effective when they are subliminal.