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
An old woman, Nanda suffered stroke for which she was given alteplase. She improved considerably. To prevent the recurrence of stroke, this patient is most likely to be treated indefinitely with : 
Select and explain. 
A. Aspirin, B. Warfarin, C. Urokinase, D. Enoxaparin
A: Aspirin
Answer: A: Aspirin 
Explanation: None