A Client Taking Warfarin (Coumadin)should Be Instructed to Avoid Herbal

A client taking warfarin (Coumadin) should be instructed to avoid herbal supplements such as green tea,ginkgo,feverfew,garlic,cranberry,chamomile,and ginger.The client asks the nurse why these items should be avoided.The nurse bases her response on what knowledge?

A) These items increase the risk of bleeding.
B) These items cause severe hypotension.
C) These items decrease the effect of the warfarin (Coumadin) .
D) These items cause severe headache.