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': "Abnormal increase in the amplitude of 'U' wave is seen with \nSelect and explain. \nA. Amiodarone, B. Hypokalemia, C. Quinidine, D. All of the above", 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. d (All of the above) (Ref. Harrison's Internal medicine, p. 1314; Topol cardiology Textbook, p. 158)'U' Wave# Occurs due to repolarisation of papillary muscles (Ganong Physiology p. 550, 22nd edition)# Normally upright (< 1 mm) or (< 10% of height of T wave)", 'role': 'assistant'}]