A∪B={1,3,5,7},A错误
CuA={2,4,6},CuA∪B={2,3,4,5,6},B错误
CuB={1,2,4,6,7},A∪CuB={1,2,3,4,5,6,7},C正确
CuA∪CuB={1,2,4,6,7},D错误
选C