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: Physiology
[{'content': 'The relaxation of smooth muscle is associated with a reduction in free intracellular calcium ion concentration. The effect of the reduction is \nSelect and explain. \nA. Reestablishment of inhibition of actin-myosin interaction, B. Deactivation of enzymatic activity of the individual actin molecules, C. Decreased phosphorylation of myosin molecules, D. Reduced contractile interaction by blocking the active sites of the myosin molecules', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Due to relaxation of smooth muscle, dephosphorylation of myosin by myosin light chain phosphatase.', 'role': 'assistant'}]