C

Large series of ruptured/emergency abdominal aortic aneurysm repairs consistently report operative mortality in the high-30s to mid-40s percent range—for example, 36 % in a Danish multicentre review (Olsen, 1990, PMID 2363212) and 45 % in a Japanese series (Morishita, 1986, PMID 3773359). These figures best align with the 40 % choice.