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: Anatomy
[{'content': 'JG cells (Juxta glomerular apparatus) are ? \nSelect and explain. \nA. Macula densa, B. Smooth muscular cells of afferent aeriole, C. Smooth muscular cells of afferent aeriole, D. Islets of epithelial cells', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e., Smooth muscle cells of afferent aeriole', 'role': 'assistant'}]