Research on Messages to Promote Recycling (Werner Et Al

Research on messages to promote recycling (Werner et al., 2004) examined the use of persuasive messages through three conditions; control condition, no message, validation condition, acknowledging any inconvenience and thanking those who comply, and the persuasion message about the importance of recycling. Which of the following statements is true?

A) The persuasion message was the only condition that increased recycling.
B) The validation message was the only condition that increased recycling.
C) Use of messages significantly increased recycling, including the control group.
D) The use of either validation or persuasion message increased recycling significantly.