You're interested in the effect of lighting on proofreading. In your study, half of your participants read a draft of a story in bright lighting, while the other half read the draft in dim light. You record the number of proofreading errors every participant makes. What is the dependent variable in this situation? a) The complexity of the words in the draft b) Number of proofreading errors c) Number of students in the study d) The lighting used in the room