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
A 52-year-old woman presents with polyuria, polydypsia, constipation, and fatigue. She has no significant past medical history, and she is not on any medications. She was recently diagnosed with hyperparathyroidism.Select the characteristic ECG findings. 
Select and explain. 
A. shortened PR interval, B. lengthened PR interval, C. lengthened QU interval, D. shortening of the QT interval
D: shortening of the QT interval
Answer: D: shortening of the QT interval 
Explanation: With severe hypercalcemia, the QT interval is markedly shortened. There is a correlation between the length of QT interval and the degree of hypercalcemia.