Chronic constipation

An elderly patient presents with chronic constipation and an acute episode of lower abdominal pain, fever and increase white blood cell count. Radiologic images reveal herniation of the colon and there is concern for peritonitis and possible sepsis. Based on this pathophysiologic information, what is the most likely diagnosis?

a. irritable bowel syndrome

b. chrons disease

c. inflammatory bowel disease

d. diverticulosis