This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood, Subject name: Medicine
[{'content': 'A 30-year-old male attends blood transfusion department for platelet apheresis. He has not donated blood before. During apheresis, he suddenly feels tingling around the mouth, numbness in the arm. An ECG was taken and shows ST segment elevation. What is the reason? \nSelect and explain. \nA. Blood phobia, B. Due to first time transfusion, C. Citrate toxicity, D. Hypothermia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: ANS. CThe diagnosis of the above question is hypocalcemia due to excess citrate producing symptoms of hypocalcemic tetany.ECG--characteristics of hypocalcemia', 'role': 'assistant'}]