题目

阅读理解 Some people like modem art, while others say that is rubbish. But a cleaner who works in the Tate Gallery in London isn't able to tell the difference. The woman, whose name isn't known, mistook a work of art by the German painter Gustav Metzger for a bag of rubbish, and threw it out with other bags. The plastic bag, which contained pieces of paper and cardboard, was later recovered outside the gallery, but the artist thought that it was too damaged to be put on show again. 78-year-old Mr Metzger explained that the exhibit, which he said was a copy of a similar work he had created 已知函数y=f（x）的定义域和值域都是[-1，1]（其图象如图所示），函数g（x）=sinx，x∈[-π，π]．定义：当f（x1）=0（x1∈[-1，1]）且g（x2）=x1（x2∈[-π，π]）时，称x2是方程f（g（x））=0的一个实数根．则方程f（g（x））=0的所有不同实数根的个数是（　　） A、2B、4C、6D、8