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: Pharmacology
[{'content': 'All known effects of cyclic AMP in eukaryotic cells results from: \nSelect and explain. \nA. Activation of the catalytic unit of adenylate cyclase, B. Activation of synthetase, C. Activation of protein kinase, D. Phosphorylation of G protein', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Cyclic AMP exerts most of its effects by stimulating\xa0cAMP-dependent protein kinases. These phosphorylate enzymes resulting in their activation or inhibition.', 'role': 'assistant'}]