A company that manufactures drugs used to treat heart disease wants to determine if a new drug and exercise can affect cholesterol levels. What are the independent variable (IV) and the dependent variable (DV) in this proposed study? Group of answer choices a. the DV is cholesterol levels, the IVs are the drug and exercise b. the DV is exercise, the IVs are the drug and cholesterol levels c. the DV is the number of heart attacks, the IVs are the drug and cholesterol levels d. the IVs are the drug and cholesterol levels, the DV is the amount of exercise