The Nurse Is Converting a Client's Continuous IV Infusion to a Saline

The nurse is converting a client's continuous IV infusion to a saline lock. Which guideline is recommended for this procedure?

A) Stop the infusion and unclamp the tube to allow air to flow out of the line.
B) Replace the primary IV tubing with a PICC line.
C) Flush the lock with 2 to 3 mL of heparin every 4 hours to prevent clogging.
D) Flush the lock with 2 to 3 mL of saline every 8 hours or as ordered.