You are answering a USMLE-style medical question. Question: A 9-month-old boy is brought to the physician by his mother because of intermittent watery diarrhea for several months. Pregnancy and delivery were uncomplicated. He was diagnosed with eczematous dermatitis at 3 months old. His height and weight are below the 5th percentile. Immunologic evaluation shows a defect in activated regulatory T cells. A genetic analysis shows a mutation in the FOXP3 gene. This patient is at increased risk for which of the following? Options: A) Hemorrhagic diathesis B) Ocular telangiectasias C) Autoimmune endocrinopathy D) Retained primary teeth Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.