You are answering a USMLE-style medical question. Question: A 23-year-old woman visits her obstetrician for an antenatal appointment. She is at the 24th week of gestation. She has had type 1 diabetes mellitus for 5 years and is on insulin. She also has mitral stenosis, for which she has been advised to undergo a balloon valvotomy. Her temperature is 37.1°C (98.7°F), blood pressure is 120/60 mm Hg, and pulse is 90/minute. Her random blood glucose is 220 mg/dL and HbA1C is 8.5%. She wants to discuss possible complications concerning her pregnancy. Which of the following cardiac complications is her infant at high risk for? Options: A) Hypertrophic obstructive cardiomyopathy B) Transient hypertrophic cardiomyopathy C) Tetralogy of Fallot D) Mitral valve prolapse Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.