Rationale: A. This is incorrect because tissue plasminogen activator (tPA) is most beneficial when given early, ideally within 3 hours of symptom onset (and up to 4.5 hours in selected patients). Early administration improves cerebral blood flow, limits infarct size, and enhances neurologic recovery. Therefore, onset less than 3 hours is not a reason to withhold tPA. B. This is incorrect because transient ischemic attacks (TIAs) resolve spontaneously and do not involve persistent cerebral vessel occlusion. Since neurologic deficits are temporary and no active clot remains, tPA is not indicated and would expose the patient to unnecessary bleeding risk. C. This is incorrect because increased intracranial pressure (ICP), often associated with cerebral edema or intracranial bleeding, is a contraindication to tPA. Administering a thrombolytic in this situation significantly increases the risk of intracranial hemorrhage and can worsen patient outcomes. D. This is correct because tPA is not recommended if the onset of ischemic stroke symptoms occurred more than 3 hours ago (or beyond the extended window for select patients). After this time, brain tissue damage becomes irreversible, and the risk of hemorrhagic transformation outweighs the potential benefit. Establishing the exact time of onset is critical to determine eligibility and ensure safe administration of tPA.