A nurse is caring for a client who has an indwelling urinary catheter. The nurse notes that sediment is present in the urine. Which of the following actions should the nurse take to obtain a sterile urine specimen?

A. Using the balloon port can contaminate the specimen and is not the proper method to obtain a sterile sample. B. Disconnecting the catheter from the collection tubing can increase the risk of infection. C. Unclamping the collection port could cause urine to back up into the catheter and introduce bacteria. D. The retention port should be used to obtain a sterile specimen from the catheter, as it is designed for this purpose.