Which Set of Instructions Is Most Appropriate When Preparing the Patient

Which set of instructions is most appropriate when preparing the patient for collection of a 24-hour creatinine clearance for a prelithium workup?

A) "Collect all urine when you wake up and for 12 hours thereafter, and then discard all collected urine, noting the time. Begin again to collect all urine, and refrigerate it for the next 12 hours after your blood is drawn."
B) "Discard your first morning urine on awakening, and then begin to time and collect your urine. Keep it refrigerated in a clean 3-L plastic container. Your blood may be drawn at any time during the collection."
C) "Sign this consent form; then collect your urine for the next 24 hours after discarding the first urine of the morning and then refrigerate the clean 3-L container between voidings."
D) "Sign this consent form, and then begin to collect your urine in a clean 3-L plastic container for 24 hours. You may refrigerate the urine collection if you wish."