This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
[{'content': 'Which drugs action needs insulin presence to produce its therapeutic action? \nSelect and explain. \nA. Glibenclamide, B. Nateglinide, C. Pioglitazone, D. Empagliflozin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Metformin and glitazones require insulin for their action as they are just insulin sensitizers not releasers. They sensitize the tissue to insulin hence require insulin for their action. Ref: KD Tripathi 8th ed.', 'role': 'assistant'}]