Twelve years after menopause, a 60-year-old woman undergoes laparotomy for an ovarian carcinoma. The ovarian tumor that is most likely to respond to radiotherapy is which of the following?

Dysgerminoma (like seminoma in men) is very radiosensitive. The Krukenberg's tumor is a metastatic tumor to the ovary and is not treated by radiation. The other tumors are best treated by surgery. The Brenner tumor is most often a benign tumor. Arrhenoblastomas and granuloso cell tumors are hormone-producing tumors.