题目

When Charles Stratton was five, he stopped growing. His mother took him to see the famous showman, P.T.Barmum. Mr Barmum thought a small person would be the perfect addition to his show. He hired Charles’ parents along with him, and they traveled the world together.He gave the two-foot-tall Charles a name, General Tom Thumb. He taught Tom how to sing, dance, act, and tell jokes. When he felt Tom was ready to perform on stage, he made up ads. To stir up（激起）great interest, he said that Tom was eleven years old and had come from England.During the show, Tom fought battles pretendedly wi若曲线的一条切线与直线垂直，则的方程为（      ）A．B．C．D．