Why Must Vitamin K Intake Be Consistent When Taking the Anti-Coagulant

Why must vitamin K intake be consistent when taking the anti-coagulant drug sodium warfarin?

A) Because warfarin functions by interfering with the formation of active vitamin K,the amount of vitamin K consumed will influence the dose of the drug required.
B) Because warfarin functions by promoting with the formation of active vitamin K,the amount of vitamin K consumed will influence the dose of the drug required.
C) Because warfarin functions as a vitamin K agonist,the less vitamin K consumed the more effective the drug is.
D) Sodium warfarin acts through metabolism unrelated to vitamin K.