An obstructing rectosigmoid mass with a caecum of 11 cm is an acute mechanical large-bowel obstruction with a caecum close to perforation. After rapid resuscitation, this needs urgent relief of the obstruction, usually by operation. Prolonged NGT suction or NPO observation (D, E) wastes time, and a barium enema is not appropriate. The old bank chose B (colonoscopy and biopsy first). One summary suggests colonoscopy and a rectal tube to relieve obstipation, but a diagnostic work-up should not delay decompression.