This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid and electrolytes, Subject name: Medicine
[{'content': 'True about hyperkalemia - \nSelect and explain. \nA. Stop hea in systole, B. Insulin-Glucose is given, C. ECG is diagnostic, D. Serum potassium more than 5.2 mmol\\/L', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Classically, the electrocardiographic manifestations in hyperkalemia progress from tall peaked T waves (5.5-6.5 mM), to a loss of P waves (6.5-7.5 mM) to a widened QRS complex (7.0-8.0 mM), and, ultimately, a to a sine wave pattern (>8.0 mM). However, these changes are notoriously insensitive, paicularly in patients with chronic kidney disease or end-stage renal disease. ( ref: harrisons principles of internal medicine, 19E page 310)', 'role': 'assistant'}]