A hemodynamically normal 10-year-old girl is hospitalized for observation after a Grade III (moderately severe) splenic injury has been confirmed by computed tomography (CT). Which of the following mandates prompt celiotomy (laparotomy)? Select one: a. b. serum amylase of 200 leukocyte count of 14,000 C. evidence of retroperitoneal hematoma on CT scan d. development of peritonitis on physical exam e. fall in the hemoglobin level from 12 g/dL to 8 g/dL over 24 hours