听力原文： The UN Security Council has unanimously adopted a resolution renewing the UN peace-keeping force in Rwanda for another 6 months while reducing its size by more than half. (26[C]) The UN resolution authorizes the reduction of the UN assistance mission in Rwanda (25[A]) from 5000 troops to 2300 troops within three months and to 1800 troops within four months. The resolution is a compromise between a proposal by UN Secretary General to cut the UN force in half and Rwandans' wish for an even larger reduction. Rwandan authorities say they have assumed responsibility for national security following last year's Hutu-led genocide, reducing the need for UN peace-keeping. (26[B], [D]) The UN force will also help with the training of the national police force and with the delivery of humanitarian aid.
The reduction of ______ UN peace-keeping troops within 4 months from Rwanda is authorized.
A．5000
B．2300
C．3200
D．1800