Select the best definition of Ischaemic stroke.

A. A macrocytic anaemia caused by impaired DNA synthesis, often from folate or vitamin B12 deficiency. B. Persistent airflow limitation commonly related to smoking or noxious exposure. C. Hyperglycaemia with ketonaemia and metabolic acidosis due to severe insulin deficiency. D. Neurological deficit caused by interruption of cerebral blood flow due to arterial occlusion.