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: Medicine
[{'content': 'Gestational diabetes develops only during \nSelect and explain. \nA. Old age, B. Younger age, C. Pregnancy, D. Infancy', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]