This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Neuraxial Blockade, Subject name: Anaesthesia
[{'content': 'For a 78 yr old man for trans urethral resection of prostate, ideal anesthetic method is spinal anesthesia, this is because \nSelect and explain. \nA. General anesthesia causes more bleeding than spinal, B. Signs of hyponatremia can easily be detected under spinal, C. Spinal anesthesia abolishes the obturator nerve stimulation by electro cautery, D. Obstructive uropathy and renal failure may be associated with prostatic enlargement', 'role': 'user'}, {'content': 'Answer: B \nExplanation: TURP syndrome may occur at any time perioperatively and has been observed as early as few minutes after surgery has staed and as late as several hours after surgery has been completed. When under regional anesthesia, the patient characteristically complains of Dizziness Headache Nausea Tight feeling in the chest and throat Shoness of breath Restlessness Confusion Retching Abdominal paint thus regional anaesthesia is preferred.', 'role': 'assistant'}]