You are answering a USMLE-style medical question. Question: A 73-year-old woman is brought to the physician by her daughter for evaluation of impaired memory and word-finding difficulties for 2 years. She was recently asked to step down from her position as volunteer accountant for a local charity organization because she was no longer able to coordinate her tasks. She reports that she has become unable to taste or smell her food. Two years later, the patient dies. At autopsy, examination of the brain shows generalized cortical atrophy. A photomicrograph of a section of the brain is shown. The inclusions indicated by the arrows are predominantly composed of which of the following substances? Options: A) Alpha-synuclein B) Amyloid-β C) Hyperphosphorylated tau D) Prion protein Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.