This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical & Surgical Illness Complication Pregnancy, Subject name: Gynaecology & Obstetrics
[{'content': 'Congenital anomalies are most severe in: \nSelect and explain. \nA. Rubella infection, B. Mumps, C. CMV, D. Toxoplasma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is a, i.e. Rubella infectionRef. Williams Obs. 23/e, p 1214"Rubella is one of the most teratogenic agents known." Ref. Williams Obs. 23/e, p 1214Rubella causes a number of serious defects in fetus. These defects may occur singly or in combination called Congenital rubella syndrome.', 'role': 'assistant'}]