Way more information is needed. Don't assume anything at this point. For example, has this ownership been the same for all years, including 2017? Was company B acquired in a 410(b)(6)(C) transaction, so that a transition period might apply? Are all of the employees ELIGIBLE employees? Perfectly ok to exclude some or all employees of a Controlled group IF you can pass coverage testing.
Based upon the ownership you give above, it would appear to be a controlled group now.