You are answering a USMLE-style medical question. Question: A 39-year-old man is brought to the physician by his wife because of personality changes over the past year. He has become increasingly irritable, loud, aggressive, and impulsive. His wife also reports jerky movements of his limbs and trunk for the past few months. His father had dementia in his mid-40s, but the details of his condition are unclear. The patient appears restless. Examination shows irregular movements of the extremities and twitching of the face and tongue. Mental status examination shows impaired memory. This patient's condition is most likely associated with which of the following changes on MRI? Options: A) Reduced hippocampal volume B) Multiple cortical and subcortical infarctions C) Degeneration of the frontal and temporal lobes D) Atrophy of the striatum Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.