You are answering a USMLE-style medical question. Question: A 5-year-old boy is brought to the physician because of facial swelling that started 5 days ago. Two weeks ago, he had a sore throat that resolved spontaneously. His temperature is 37°C (98.6°F), pulse is 107/min, and blood pressure is 94/67 mm Hg. Examination shows pitting edema of the upper and lower extremities as well as periorbital edema. The abdomen is mildly distended. Laboratory studies show: Hemoglobin 13.1 g/dL Serum Albumin 2.1 g/dL Total cholesterol 270 mg/dL Triglycerides 175 mg/dL Urine Blood negative Glucose negative Protein 4+ Leukocyte esterase negative A renal biopsy of this patient is most likely to show which of the following findings?" Options: A) Mesangial proliferation on light microscopy B) Subepithelial dense deposits on electron microscopy C) Deposits of IgG and C3 at the glomerular basement membrane on immunofluoresence D) Normal light microscopy findings Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.