A 67-year-old man with a history of hypertension and type 2 diabetes presents to the emergency department with acute onset of left-sided weakness and dysarthria. His wife reports symptom onset was approximately 2 hours ago while he was watching television. Vital signs are: BP 168/94 mmHg, HR 92/min regular, RR 18/min, temperature 37.2°C, SpO2 98% on room air. Physical examination reveals left arm and leg weakness (3/5), dysarthria, and no facial droop. Non-contrast CT of the head shows no acute hemorrhage. MRI brain with diffusion-weighted imaging demonstrates acute ischemic changes in the right middle cerebral artery territory. Cardiac examination reveals regular rate and rhythm with no murmurs; ECG shows normal sinus rhythm. Which of the following is the most appropriate next step in management?

1. A)Initiate aspirin 325 mg orally and schedule carotid ultrasound for the following day
2. B)Administer intravenous alteplase immediately and initiate aspirin after 24 hoursGABARITO
3. C)Begin intravenous heparin for anticoagulation pending identification of embolic source
4. D)Administer intravenous labetalol to achieve systolic BP <140 mmHg before thrombolysis
5. E)Perform emergent transthoracic echocardiography and defer thrombolysis pending results