This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': "The electrical potential difference necessary for a single ion to be at equilibrium across a membrane is best described by the (NOT RELATED) \nSelect and explain. \nA. Goldman equation, B. Van't Hoff equation, C. Fick's law, D. Nernst equation", 'role': 'user'}, {'content': 'Answer: D \nExplanation: .', 'role': 'assistant'}]