This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Obs), Subject name: Gynaecology & Obstetrics
[{'content': 'Which of these hormones peaks in the 1st trimester of pregnancy? \nSelect and explain. \nA. Estrogen, B. Relaxin, C. Progesterone, D. Prolactin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: (B) Relaxin', 'role': 'assistant'}]