AN, a 65-year-old man, is brought to the Accident and Emerge…

AN, a 65-year-old man, is brought to the Accident and Emergency Department 30 minutes after the onset of right-sided weakness and aphasia (difficulty in speaking). Imaging studies ruled out cerebral haemorrhage as the cause of his acute symptoms of stroke. Prompt administration of which of the following drugs is most likely to improve this patient’s clinical outcome?