This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histamine, 5-HT and PGs, Subject name: Pharmacology
[{'content': 'H1 antihistaminic having best topical activity is: \nSelect and explain. \nA. Loratidine, B. Cetrizine, C. Astemizole, D. Azelastine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Azelastine and olopatadine have maximum topical action and are therefore used for local conditions like allergic rhinitis and allergic conjunctivitis.', 'role': 'assistant'}]