A 45 year old gentleman presents with black stools for the last 2 days. He is asymptomatic otherwise. On examination there is evidence of peripheral stigmata of liver disease. His heart rate is 105 and although his blood pressure is satisfactory he has a significant postural drop. He is fluid resuscitated. After stabilising this patient, what investigation would you next do?
A.Abdominal X ray
B.Barium meal and follow through
C.Abdominal ultrasound
D.Colonoscopy
E. Upper GI endoscopy