This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
[{'content': 'ECG finding in Hypokalemia is \nSelect and explain. \nA. Absent P wave, B. Prominent U wave, C. ST elevation, D. T wave tnting', 'role': 'user'}, {'content': "Answer: B \nExplanation: (Prominent 'U' wave): (439-Davidson 21st)HyperkalemiaHypokalemia1. Earliest changes increased T wave amplitude**- Early changes flattening or inversion of T wave **2. Prolong PR interval and QRS duration- Prominent 'U' wave**3. AV conduction delay, loss of P wave- ST segment depression, prolong QU interval4. Sin wave pattern** (progressive widening of the QRS complex merging with T wave)- Prolonged PR interval, decreased voltage and widening of the QRS complex** Prolong QT interval - Hypocalcemia, SAH** Short QT interval - Hypercalcemia, digitalis glycosides", 'role': 'assistant'}]