This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood Bank & Transfusion Therapy, Subject name: Medicine
[{'content': 'Which of the following is not done before ABG? \nSelect and explain. \nA. Allen test, B. Heparin to rinse the syring, C. Flexion of wrist, D. Poking the aery at 45 degrees angle', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Done Before ABG Allen test: integrity of palmer arch. Heparin: to rinse the syringe Poking the aery at 45-degree angle. Extend wrist joint: Radial Aery tent.', 'role': 'assistant'}]