The client diagnosed with a pulmonary embolus (PE) is receiving intravenous heparin, and the healthcare provider(HCP) prescribes 5 mg warfarin orally once daily. Which statement best explains the scientific rationale for prescribing these two anticoagulants?

A. Warfarin interferes with the production of prothrombin: Warfarin works by inhibiting vitamin K–dependent clotting factors, including prothrombin. While this is true, it does not fully explain the rationale for initiating warfarin while the client is still receiving heparin. B. It takes 3–5 days to achieve a therapeutic level of warfarin, therefore bridging is necessary: Warfarin requires several days to reach therapeutic levels because it affects the synthesis of clotting factors that have long half-lives. Heparin provides immediate anticoagulation and is used as a "bridge" until warfarin becomes effective. C. Heparin is more effective when administered with warfarin: Heparin and warfarin have different mechanisms of action and are not more effective when combined long-term. Heparin is used temporarily until warfarin reaches its therapeutic effect. D. Warfarin potentiates the therapeutic action of heparin: Warfarin does not enhance the action of heparin. In fact, warfarin initially lowers protein C and S levels, which can temporarily increase clotting risk. The dual use is strictly for transitioning therapy, not to potentiate effects.