Final answer:
The independent variable(s) in a study examining the effects of imagery on stress would be the use of imagery.
Step-by-step explanation:
In a study examining the effects of imagery on stress, the independent variable(s) would be b) The use of imagery. The independent variable is the variable that is manipulated or changed by the researchers in order to observe its effect on the dependent variable. In this case, the researchers are examining the effects of using imagery on stress, so the use of imagery is the independent variable.