You are answering a USMLE-style medical question. Question: An 8-year-old girl comes to the physician because of a 2-day history of hematuria. Two weeks ago, she had a sore throat that resolved without treatment. Physical examination shows 1+ pitting edema of the lower legs and ankles. Urinalysis shows numerous RBCs and 3+ proteinuria. Her antistreptolysin O titer is elevated. Formation of which of the following is most likely involved in the underlying mechanism of this patient's symptoms? Options: A) Antigen-specific IgE binding to mast cells B) Tissue-specific antibodies C) Antigen-antibody complexes D) Presensitized CD8+ cytotoxic T-cells Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.