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
[{'content': "Abdul Khan presents with pain, numbness and impaired sensation over half of the face along with ataxia, nystagmus, dysphagia and hoarseness of voice. His pain and thermal sensations over opposite half ane impaired Horner's syndrome is present.Likely cause of the disease is thrombosis of which vessel? \nSelect and explain. \nA. AICA (Anterior inferior cerebellar artery), B. PICA (Posterior inferior cerebellar artery), C. Basilar, D. Pontine vessels", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]