This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Which of the following is the earliest conclusive evidence of intrauterine death : \nSelect and explain. \nA. Shrinking of body, B. Intra-aoic gas, C. Increased curvature of spine, D. Spalding sign', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Intra-aoic gas', 'role': 'assistant'}]