Dr. Morgendorffer wants to develop a questionnaire that measures employees' burnout. But during her literature review, she learns that burnout is a variable with three separate dimensions: exhaustion, cynicism, and detachment. Which of the following checks will help ensure that Dr. Morgendorffer's burnout questionnaire is valid? a. Ensuring that the items across all three dimensions are correlated with each other b. Ensuring that there is a high level of stability for each of the three dimensions c. Ensuring that the dimensions represent parallel forms of the questionnaire d. Ensuring that all three dimensions have been adequately represented in the questionnaire