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': 'Dopamine acts on D2 receptors that have an inhibitory effect on prolactin secretion. Now if D2 receptors are blocked, which of the following effects will not be seen: \nSelect and explain. \nA. Visual disturbance, B. Gonadal dysfunction, C. Headache, D. Excessive lactation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]