This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
A useful thrombolytic agent that leads to plasmin activation is : 
Select and explain. 
A. Vitamin K, B. Heparin, C. Streptokinase, D. Aspirin
C: Streptokinase
Answer: C: Streptokinase 
Explanation: None