This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology, Subject name: Pharmacology
Heparin acts activation of: 
Select and explain. 
A. Antithrombin III, B. Factor VIII, C. Factor II and X, D. Factor V
A: Antithrombin III
Answer: A: Antithrombin III 
Explanation: Heparin activates plasma anti thrombin III. Anti thrombin binds to and inhibits the activated thrombin and coagulation factors ( Xa and IXa). From medical pharmacology padmaja 4th edition Page no 334