This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical Illness Complicating Pregnancy, Subject name: Gynaecology & Obstetrics
[{'content': 'Congenital Infection affecting the fetus with minimal teratogenic risk is: \nSelect and explain. \nA. HIV, B. Rubella, C. Varicella, D. CMV', 'role': 'user'}, {'content': 'Answer: A \nExplanation: * HIV is not teratogenic * CMV is the commonest cause of fetal & perinatal infection * No teratogenic effects - HIV, measles, influenza * Rubella is most teratogenic agent known', 'role': 'assistant'}]