Correct answer:

(1) Intracranial birth injury. (2) Neonatal intestinal obstruction: from duodenal atresia, volvulus neonatorum or intestinal atresia, the symptoms commence within 1–2 days of birth and the vomit contains bile. (3) Enteritis: diarrhoea accompanies this. (4) Overfeeding: here, there are no other features to suggest pyloric stenosis apart from vomiting.