Answer: Vitamin K.
What is Vitamin K?
Vitamin K is an essential fat soluble vitamin that is important in maintaining normal coagulation, serving as a co-factor in the activation of several clotting factors and anticoagulant proteins.
It can be found in foods such as spinach, lettuce, kale, brocolli, and soybean/canoli oils.
Vitamin K helps to regulate the process of blood coagulation by assisting in the conversion of certain coagulation factors into their mature forms.
Hope this helps you! :)