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': 'Hypokalemia ECG changes- \nSelect and explain. \nA. Tall T wave, B. Sho QRS interval, C. Depressed ST segment, D. Absent P wave', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Hypocalcemia: The most significant sign is intermittent QT prolongation, or intermittent prolongation of the QTc (corrected QT interval) secondary to a lengthened ST segment and depressed ST segment. Although rare, this may lead to arrhythmias such as torsades de pointes, VT, or complete hea block. Ref : Harrison 20th edition pg 1435', 'role': 'assistant'}]