A 48 year old woman presents with a 3 hour history of sudden onset severe left sided abdominal pain and vomiting. Ultrasound scan suggests a ruptured right ovarian cyst and emergency laparotomy is undertaken with left salpingo-oophrectomy. The right ovary, uterus, fallopian tubes, liver and omentum appeared normal. Histology confirms a mucinous cystadenocarcinoma of the left ovary which had ruptured before surgery. The stage of the tumour is
