An otherwise healthy, right-handed 61-year-old woman was seen to have difficulty expressing herself while reading aloud 2 days ago. family members describe she had slowed speech with difficulty finding words and word substitutions, including similar sounding and similar meaning words. she then experienced an episode of complete speech arrest with staring and an outstretched right upper arm lasting 10 seconds, during which time she did not respond to her family. examination reveals normal vital signs, regular cardiac rhythm, and no carotid bruits. neurologic examination reveals decreased speech output with short phrases, omission of articles such as "the" and "a," and both semantic (similar meaning) and phonemic (similar sounding) paraphasic errors. she can follow three-step commands crossing the midline and can repeat short, but not long phrases; she also can name "thumb" and "button" but not "lapel, knuckles, ring finger, index finger"; reading and writing are similarly impaired. she seems frustrated by her speech impairment. motor exam reveals a right pronator drift with slowed fine finger movements in the right hand. sensory exam reveals intact primary sensation but inability to name objects placed in the right but not the left hand. the remainder of neurologic examination including visual field testing is normal. which of the following is the most likely underlying process?
a. frontotemporal dementia, nonfluent aphasia subtype
b. herpes simplex encephalitis in the left frontotemporal lobes
c. high-grade primary brain tumor in the left posterior frontal and parietal lobes
d. hypertensive intracerebral hemorrhage in the left thalamus
e. ischemic infarction due to left main stem middle cerebral artery occlusion