若X，Y独立同分布且X的分布函数为F(x)，则Z=max{X，Y}的分布函数是()(A)F(x)F(y)(B)F(x)(C)[F(x)](D)[F(x)][F(y)]AF(x)F(y)BF(x)C[F(x)]D[F(x)][F(y)]