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
Hypokalemia ECG changes- 
Select and explain. 
A. Tall T wave, B. Sho QRS interval, C. Depressed ST segment, D. Absent P wave
C: Depressed ST segment
Answer: C: Depressed ST segment 
Explanation: 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