This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal tract, Subject name: Pharmacology
[{'content': 'For chemotherapy induced vomiting, 5HT3 antagonist having maximum potency is: \nSelect and explain. \nA. Ondansetron, B. Granisetron, C. Dolasetron, D. Palonosetron', 'role': 'user'}, {'content': 'Answer: D \nExplanation: it is the longest acting and highest affinity towards 5HT3 receptor used in chemotherapy induced vomiting ESSENTIAL OF MEDICAL PHARMACOLOGY SEVENTH EDITION KD TRIPATHI PG NO .669', 'role': 'assistant'}]