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: Medicine
Most common cause of cerebrovascular accident is - 
Select and explain. 
A. Embolism, B. Arterial thrombosis, C. Venous thrombosis, D. Haemorrhage
A: Embolism
Answer: A: Embolism 
Explanation: None