You are answering a USMLE-style medical question. Question: A 32-year-old woman comes to the physician because of fatigue and joint pain for the past 4 months. Examination shows erythema with scaling on both cheeks that spares the nasolabial folds and two 1-cm ulcers in the oral cavity. Further evaluation of this patient is most likely to show which of the following findings? Options: A) Decreased lymphocyte count B) Increased platelet count C) Increased prothrombin time D) Decreased gamma globulin Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.