context: There are fifteen fraternities and seven sororities at the University of Chicago, as well as one co-ed community service fraternity, Alpha Phi Omega. Four of the sororities are members of the National Panhellenic Conference, and ten of the fraternities form the University of Chicago Interfraternity Council. In 2002, the Associate Director of Student Activities estimated that 8–10 percent of undergraduates were members of fraternities or sororities. The student activities office has used similar figures, stating that one in ten undergraduates participate in Greek life.
question: How many sororities belong to the National Panhellenic Conference?
answers.text: Alpha Phi Omega Four Four