The correct option is D Warfarin
Warfarin is an anticoagulant, normally used in the prevention of thrombosis and thromboembolism, the formation of blood clots in blood vessels and their migration elsewhere in the body respectively. Very few drugs are proven to be teratogen and warfarin is the first amongst them. Warfarin causes birth defects as it passes through the placental barrier and may cause bleeding in the fetus. So, the correct answer is option A.