A、Because there was enough blood stored in the city blood bank B、Because most people were instantly killed C、Because New Yorkers

The terrible destruction of the World Trade Center, on September 11th 2001, has united the States in a way that they have not known for many years. It has also united most of the world. We will never forget what happened on that day of tenor.
    Two planes, carrying passengers and crew, were hijacked by terrorists and flown into the two towers of the World Trade Center, which later collapsed.
    Two other planes were also hijacked. One was thrown against the Pentagon; in the other, heroic passengers fought the terrorists, making the plane crash in a forest in Pennsylvania That resistance probably saved hundreds of lives.
    In all, over 5 000 people--from over 60 different countries--died in New York or in Washington: among them there were over 200 people from the emergency services, the police and the New York Fire Department.
    While frightened workers poured downstairs to escape from the two burning towers, emergency workers were going upstairs, climbing towards the death and destruction above them; they were climbing to their own deaths. Others remained below, to receive the casualties as they were brought down. They too died when the 104 stories of the massive buildings above them collapsed in a fury of dust and smoke and masonry.
    "They were the bravest men I’ve ever seen," said a man who escaped from the towering inferno of the world Trade Center.
    All over the USA, people offered their blood to help the injured; but in fact there was not a lot of need for blood. When the massive buildings collapsed, most people died instantly. Only a few injured people were brought out from the debris.
    The disaster united Americans in grief, because almost every American felt personally attacked. The fanatical murderers who planned this attack, and carried it out, thought that they would make America weaker; in fact, they have made it stronger. Almost the whole world has been united in horror and sympathy.