This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'The resting membrane potential of cardiac muscle is: \nSelect and explain. \nA. -90, B. -60, C. -70, D. All', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The resting membrane potential of cardiac muscle is:-90 Ref:Guyton and Hall textbook of medical physiology 12th edition,page number:81', 'role': 'assistant'}]