This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
[{'content': 'A person taking tricyclic antidepressants presents with blurred vision and dry mouth. These adverse effects results due to blockade of: \nSelect and explain. \nA. M3 muscarinic receptors, B. GABA receptor, C. H1 histamine receptors, D. 5HT2 receptors', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Anticholinergic adverse effects of TCAs include dry mouth, constipation, blurring of vision, urinary retention, etc. REF:KD TRIPATHI 8TH ED.', 'role': 'assistant'}]