Suppose that where you work, people often fail to recycle. In the copy room, for example, there is ...

Suppose that where you work, people often fail to recycle. In the copy room, for example, there is both a recycling box and a trash bin, and many people put used paper in the trash instead of the recycling box.
 
  Which of the following is most likely to get people to recycle more?
  a. Put up a sign that says, Many of you are putting paper in the trashplease recycle it instead.
  b. Put up a sign that says, Please recycle. We're already doing better than other units in the company, but there is room to improve.
  c. Set an example by cleaning up the copy room and putting all the paper that was in the trash bin into the recycling box.
  d. Put all the paper that was in the trash bin into the recycling box, except for one big, noticeable paper product (e.g., a poster) into the trash bin.