You are answering a USMLE-style medical question. Question: A 55-year-old man with a history of chronic glomerulonephritis due to IgA nephropathy presents to your office with bone pain. Which of the following laboratory findings would you most expect upon analysis of this patient's serum? Options: A) Increased PTH, decreased calcium, increased phosphate, decreased calcitriol B) Decreased PTH, increased calcium, increased phosphate, increased calcitriol C) Decreased PTH, decreased calcium, increased phosphate, decreased calcitriol D) Normal PTH, normal calcium, normal phosphate, normal calcitriol Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.