What Effects Have Subliminal Self-Help Tapes Been Shown to Have

What effects have subliminal self-help tapes been shown to have on behaviour?

A) The subliminal messages delivered verbally have been shown to have powerful and long-lasting impact on behaviour.
B) The content of subliminal self-help tapes has been shown to have a powerful effect on behaviour.
C) Participants' beliefs about the content of subliminal self-help tapes have been shown to have powerful effects on both perceived and actual behavioural changes.
D) Participants' beliefs about the content of subliminal self-help tapes have been shown to have powerful effects on perceived,but not actual,behavioural changes.