One similarity between the Knights of Labor and the American Federation of Labor is that both?

Question

1- were limited to skilled workers
2 - nominated candidates for national political office
3 - were organized on a nationwide basis
4 - were advocates of economic and social revolution

Answer 1

the answer you are seeking is 3. Both groups were national organizations. The Knights were a national collection of workers, while the AFL was a Federation of existing local craft unions from across the nation.

The Knights were open to all sorts of workers, so 1 isn't it. The Knights mostly tried to stay out of politics, and the AFL didn't nominate candidates either, so it's not 2. And 4 is not it - neither of these groups were radicals who wanted great social changes.

Answer 2

3. were organized on a nationwide basis