题目

In 1826, a Frenchman named Niepce needed pictures for his business. But he was not a good artist. So he invented a very simple camera, He put it in a window of his house and took a picture of his garden. That was the first photo.The next important date in the history of photography(摄影术) was in 1837. That year, Daguerre, another Frenchman, took a picture of his reading-room. He used a new kind of camera in a different way. In his picture you could see everything very clearly, even the smallest thing. The kind of photo was called a Daguerreotype.Soon, other people began to use Daguerre's w等腰三角形的一边长为4，另一边长为3，则它的周长为（ ）A．11 B．10C．10或11D．以上都不对