Which of the following statements about anticoagulant drugs is correct?

• A. Heparin and aspirin
• B. Warfarin and clopidogrel
• C. Heparin and Warfarin
• D. Alteplase and streptokinase

Answer: (C)

Anticoagulants are drugs that slow or prevent the coagulation cascade to stop clot formation, not drugs that affect platelets or dissolve clots. Heparin acts quickly by enhancing antithrombin III, which in turn inhibits thrombin and factor Xa, giving rapid anticoagulation. Warfarin, on the other hand, reduces the production of vitamin K–dependent clotting factors II, VII, IX, and X, providing a slower, longer‑acting anticoagulant effect. The other options mix in antiplatelet drugs (aspirin, clopidogrel) or thrombolytics (alteplase, streptokinase), which either prevent platelet aggregation or actively dissolve clots, not prevent their formation. So the statement that pairs two true anticoagulants—heparin and warfarin—best fits.