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': 'Gestational diabetes is usually diagnosed at: \nSelect and explain. \nA. I trimester, B. II trimester and and III trimester beginning, C. At time of delivery, D. Perinatal period', 'role': 'user'}, {'content': 'Answer: B \nExplanation: II trimester and and III trimester beginning', 'role': 'assistant'}]