This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Endothelial derived relaxing factor is associated with \nSelect and explain. \nA. Ras, B. C- myc, C. Bcl, D. nNOS', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref Robbins 8/p60;7/e,72-73 ;9/e p80 , it is firmly established this substance is nitric oxide (NO).Endothelium produces NO which then diffuses to the vascular smooth muscle tissue, although these seems to be evidence that vasodilatory may also be of neuronal origin, rather than endothelial. NO is produced by the enzyme nitric oxide synthase and it relaxes smooth muscle tissue by promotig the synthesis of cGMP.', 'role': 'assistant'}]