题目

A famous teacher was speaking to the students at our school. He began his lesson by holding up a ¥100 bill. Then he said to the three hundred students, “Who would like this ¥100 bill?” The students began to put up their hands at once.Then he said, “I am going to give this ¥100 to one of you, but first, let me do this.” He then made the bill into a ball. Then he said, “Who wants it now?” The hands went back into the air.“Well,” he said, “What if I do this?” and he dropped it on the floor and stepped on it. He picked up the dirty, crumpled bill and said, “Who still wants在中，，则的形状是(   　 ) A．直角三角形　　B．锐角三角形     C．钝角三角形　 　　D．正三角形