This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CLINICAL TRIALS, DRUG LABEL, Subject name: Pharmacology
[{'content': 'Which of the following statements about phase IV clinical trials is true? \nSelect and explain. \nA. It is done for pediatric drugs, B. It is done for rare drugs, C. It is post-marketing surveillance of drugs, D. It is also called human pharmacology and safety studies', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Phase Name Purpose I Human Pharmacology and safety To know the Maximum tolerable dose > Dose > Pharmacokinetics > Safety II Therapeutic Exploratory To establish therapeutic efficacy, dose ranging and ceiling effect III Therapeutic Confirmatory To Confirm therapeutic efficacy and To establish the value of drug in relation to existing therapy IV Post-Marketing Surveillance To know rare and long term adverse effects. Special populations like pregnancy and children can be tested 0 (ZERO) Micro-dosing studies To know pharmacokinetics Could avoid costly phase I studies for drugs with unsuitable pharmacokinetics', 'role': 'assistant'}]