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
The most common cause of embolic stroke 
Select and explain. 
A. Non rheumatic atrial fibrillation, B. Carotid aery atherosclerosis, C. Paradoxical embolism, D. LV aneurysm
A: Non rheumatic atrial fibrillation
Answer: A: Non rheumatic atrial fibrillation 
Explanation: Ans. is 'a' i.e., Non rheumatic atrial fibrillation No rheumatic atrial fibrillation leads to clot formation in left atrial appendage that can embolize to the brain leading to neurological dificits