A client is receiving heparin sodium 5000 units IV and oral warfarin sodium 2.5 mg PO for thrombophlebitis in the left leg. The nurse educated the client that heparin and warfarin are both used because:

C smaller doses of both drugs can be used with this method of administration. D this combination provides immediate maximum protection against clot formation. A the heparin provides anticoagulation until the warfarin becomes effective. B this combination facilitates the dissolving of the clot.