You are answering a USMLE-style medical question. Question: A 5-year-old female suffers from recurrent infections by Aspergillus species, Pseudomonas species, and Staphylococcus aureus. The patient's neutrophils are examined in the laboratory and they fail to react during the nitroblue tetrazolium test. Which of the following is most likely dysfunctional in this patient? Options: A) Immunoglobulin class switching B) Superoxide dismutase C) Myeloperoxidase D) Respiratory burst Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.