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': 'Phase IV of clinical trials collect information specially about: \nSelect and explain. \nA. Drug efficacy, B. Drug potency, C. Drug toxicity, D. Pharmacokinetics of the drug', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]