听力原文： A twenty-year action plan for cutting the rate of world population growth is exp

ected to win wide approval today in Cairo. Delegates at the UN-sponsored conference on population complete the final talks on the plan Monday. The document is non-binding but it will serve as a guideline for countries and states that fund health care and family planning programs. The world population of 5.7 billion currently is growing at more than 90 million a year.

Who sponsored the conference on population？

A．Cairo.

B．The United Nations.

C．The World Bank.

D．The World Health Organization.